Nutrition and health

Objectives:
Can the biomarker miRNAs predict Alzheimer's disease?

Study design:
This review article included 10 studies containing 770 Alzheimer's disease and 664 normal controls (persons without Alzheimer's disease).

Results and conclusions:
The investigators found miRNAs presented excellent diagnostic performance and the overall sensitivity was 0.80 [95% CI = 0.75-0.83], specificity was 0.83 [95% CI = 0.78-0.87] and diagnostic odds ratio was 14 [95% CI = 11-19].

The investigators found subgroup analysis suggested that the Caucasian group and blood group showed a better performance in Alzheimer's disease diagnosis and the diagnostic odds ratio was 42 and 34, respectively.

The investigators concluded that miRNAs may be a promising biomarker for Alzheimer's disease.

Original title:
Blood circulating miRNAs as biomarkers of Alzheimer's disease: a systematic review and meta-analysis by Zhang YH, Bai SF and Yan JQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31385521

Additional information of El Mondo:
Find more information/studies on dementia and elderly.

Objectives:
Does alcohol consumption increase of risk of osteoporosis?

Study design:
This review article included  3 case control studies, 2 cohort studies and 1 cross-sectional study.

Results and conclusions:
The investigators found no association between consuming 0.5-1 drinks per day and the risk of developing osteoporosis [adjusted RR = 1.38, 95% CI = 0.90-2.12].
No association because RR of 1 was found in the 95% CI of 0.90 to 2.12. RR of 1 means no risk/association.

The investigators found compared with abstainers of alcohol, persons consuming 1-2 drinks per day had 1.34 times the risk of developing osteoporosis [adjusted RR = 1.34, 95% CI = 1.11-1.62].

The investigators found compared with abstainers of alcohol, persons consuming 2 drinks or more per day had 1.63 times the risk of developing osteoporosis [adjusted RR = 1.63, 95% CI = 1.01-2.65].

The investigators found a positive association between alcohol consumption and osteoporosis in the case-control studies [adjusted OR = 2.95, 95% CI = 1.78-4.90].

The investigators concluded there is a positive relationship between alcohol consumption, particularly 1 drink or more per day and osteoporosis.

Original title:
The effect of alcohol on osteoporosis: A systematic review and meta-analysis by Cheraghi Z, Doosti-Irani A, Almasi-Hashiani A, […], Mansournia MA.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30844616

Additional information of El Mondo:
Find more information/studies on alcohol consumption and elderly.

Objectives:
Do older adults benefit from high protein intake (>0.8 g/kg body weight/day)?

Study design:
This review article included 12 cohort studies and 1 RCT.
Studies had an intervention duration of at least 6 months.

Results and conclusions:
The investigators found meta-analysis of the cohort studies showed that high vs low protein intake resulted in a statistically significant decrease of 11% for hip fractures [pooled HR = 0.89, 95% CI = 0.84 to 0.94, p 0.001, I2 = 0.0%, p = 0.614].
Sensitivity analyses showed that there was no single study affecting the overall estimate considerably.

The investigators concluded there is an association between a dietary protein intake above the current RDA of 0.8 g/kg body weight/day and a reduced hip fracture risk in older adults. In comparison with younger adults, the body of evidence from the included studies is not strong enough to increase the protein recommendation for older adults with respect to bone health.

Original title:
High Versus low Dietary Protein Intake and Bone Health in Older Adults: a Systematic Review and Meta-Analysis by Groenendijk I, den Boeft L , [...], de Groot LCPGM.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6704341/

Additional information of El Mondo:
Find more information/studies on protein and elderly.

A protein intake higher than 0.8 g/kg body weight/day corresponds to a diet with a minimum of 11 En% protein. The easiest way to follow a diet with at least 11 En% protein is to choose only products that contain at least 11 En% protein. These products from the supermarket contain at least 11% En% protein.
 

Objectives:
Do low folate levels and vitamin B12 levels increase risk of depression among the aged people?

Study design:
This review article included both gender data of 11 folate-related (7,949 individuals) and 9 B12-related studies (6,308 individuals) and gender-specific data of 4 folate-related (3,409 individuals) and 3 B12-related studies (1,934 individuals).

Results and conclusions:
The investigators found low folate levels significantly increased risk of depression among the aged people with 23% [OR =1.23, 95% CI =1.07-1.43]. 

The investigators found low vitamin B12 levels significantly increased risk of depression among the aged people with 20% [OR =1.20, 95% CI =1.02-1.42]. 

The investigators found in subgroup analysis low vitamin B12 levels significantly increased risk of depression among the aged women with 33% [OR =1.33, 95% CI =1.02-1.74]. 

The investigators concluded both low folate levels and low vitamin B12 levels increase risk of depression among the aged people.

Original title:
Folate and B12 serum levels in association with depression in the aged: a systematic review and meta-analysis by Petridou ET, Kousoulis AA, [...], Stefanadis C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/26055921

Additional information of El Mondo:
Find more information/studies on vitamin B12, folate and elderly.
 

Objectives:
Findings from observational studies and clinical trials on the associations between vitamin E and dementia remain controversial. Therefore, this review article has been conducted.

Do low vitamin E levels increase risk of Alzheimer's disease (AD) or age-related cognitive deficits and mild cognitive impairment (MCI)?

Study design:
This review article included 31 studies.

Results and conclusions:
The investigators found individuals with Alzheimer's disease had lower circulatory concentrations of α-tocopherol (vitamin E) compared with healthy controls [SMD = -0.97, 95% CI = -1.27 to -0.68, p  0.00001].

The investigators found individuals with age-related cognitive deficits had lower circulatory concentrations of α-tocopherol (vitamin E) compared with healthy controls [SMD = -0.72, 95% CI = -1.12 to -0.32, p  0.0005].

The investigators found individuals with mild cognitive impairment had lower circulatory concentrations of α-tocopherol (vitamin E) compared with healthy controls [SMD = -0.72, 95% CI = -1.12 to -0.32, p  0.0005].

The investigators found levels of β-, γ- and δ-tocopherols did not significantly differ between groups of Alzheimer's disease and age-related cognitive deficits compared to controls.

The investigators concluded that lower α-tocopherol (vitamin E) levels have a strong association with Alzheimer's disease and mild cognitive impairment supporting evidence for the role of diet and vitamin E in Alzheimer's disease risk and age-related cognitive decline.

Original title:
A meta-analysis of peripheral tocopherol levels in age-related cognitive decline and Alzheimer's disease by Ashley S, Bradburn S and Murgatroyd C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31661399

Additional information of El Mondo:
Find more information/studies on vitamin E and elderly.
 

Objectives:
Serum uric acid (SUA) accounts for about 50% of extracellular antioxidant activity, suggesting that hyperuricemia (an abnormally high level of uric acid in the blood) may have a protective role in diseases characterized by high levels of oxidative stress, such as osteoporosis. Therefore, this review article has been conducted.

Does a high serum uric acid level (also called hyperuricemia) increase bone mineral density (BMD)?

Study design:
This review article included 19 cross-sectional studies with a total of 55,859 participants.

Results and conclusions:
The investigators found in 6 studies that subjects with higher serum uric acid levels had significantly higher bone mineral density values for the spine [SMD = 0.29, 95% CI = 0.22-0.35, I2 = 47%].
Simple correlation analyses substantially confirmed this finding.

The investigators found in 7 studies that subjects with higher serum uric acid levels had significantly higher bone mineral density values for total hip [SMD = 0.29, 95% CI = 0.24-0.34, I2 = 33%].
Simple correlation analyses substantially confirmed this finding.

The investigators found in 6 studies that subjects with higher serum uric acid levels had significantly higher bone mineral density values for femoral neck [SMD = 0.25, 95% CI = 0.16-0.34, I2 = 71%].
Simple correlation analyses substantially confirmed this finding.

The investigators found in 3 studies that an increase of one standard deviation in serum uric acid levels significantly reduced risk of new fractures with 17% [HR = 0.83, 95% CI = 0.74-0.92, I2 = 0%].

The investigators found no significant differences between men and women, although data about women were limited.

The investigators concluded a high serum uric acid level is independently associated with higher bone mineral density values and a lower risk of fractures, supporting a protective role for uric acid in bone metabolism disorders.

Original title:
Hyperuricemia protects against low bone mineral density, osteoporosis and fractures: a systematic review and meta-analysis by Veronese N, Carraro S, […], Cereda E.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/27636234

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Find more information/studies on elderly.
 

Objectives:
Do dietary intakes of soy, soy isoflavones and soy protein reduce risk of mortality from all causes, cancers and cardiovascular diseases?

Study design:
This review article included 23 prospective cohort studies with an overall sample size of 330,826 participants.

Results and conclusions:
The investigators found soy/soy products consumption significantly reduced risk of mortality from cancers with 12% [pooled relative risk = 0.88, 95% CI = 0.79 to 0.99, p = 0.03, I2 = 47.1%].

The investigators found soy/soy products consumption significantly reduced risk of mortality from cardiovascular diseases with 15% [pooled effect size = 0.85, 95% CI = 0.72 to 0.99, p = 0.04, I2 = 50.0%].

The investigators found such significant associations were also observed for all-cause mortality in some subgroups of the included studies, particularly those with higher quality.

The investigators found in addition, higher dietary intake of soy was associated with decreased risk of mortality from gastric, colorectal and lung cancers as well as ischemic cardiovascular diseases.

The investigators found participants in the highest category of dietary soy isoflavones intake had a 10% lower risk of all-cause mortality compared with those in the lowest category.

The investigators found that a 10-mg/day increase in dietary intake of soy isoflavones was associated with 7% and 9% decreased risk of mortality from all cancers and breast cancer, respectively.

The investigators found for each 5-g/day increase in consumption of soy protein a 12% reduction in breast cancer death.

The investigators found, however, dietary intake of soy protein was not significantly associated with all-cause and cardiovascular diseases mortality.

The investigators concluded that soy and its isoflavones consumption favorably influence risk of mortality. In addition, soy protein dietary intake is associated with a decreased risk in the mortality of breast cancer. These findings support the current recommendations to increase intake of soy for greater longevity.

Original title:
Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies by Nachvak SM, Moradi S, […], Sadeghi O.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31278047

Additional information of El Mondo:
Find more information/studies on soy consumption, cardiovascular diseases and breast cancer right here.

 

Objectives:
Does a high blood homocysteine level increase risk of cognitive impairment, like Alzheimer's disease and vascular dementia?

Study design:
This review article included 28 prospective cohort studies with 2,557 cases (1,035 all-cause dementia, 530 Alzheimer's disease, 92 vascular dementia and >900 cognitive impairment without dementia (CIND)) among 28,257 participants.
 
The average follow-up period ranged from 2.7 to 35 years.

There was no clear evidence of publication bias with Begg's and Egger's tests for Alzheimer dementia [p = 0.806, 0.084, respectively].

Results and conclusions:
The investigators found there was a clear linear dose-response relationship between blood homocysteine concentration and risk of Alzheimer-type dementia [p > 0.05 for non-linearity].

The investigators found for every 5 μmol/L increase in blood homocysteine a significantly increased risk of 15% [pooled RR = 1.15, 95% CI = 1.04 to 1.26, I2 = 56.6%, n = 5] for Alzheimer-type dementia.
Sensitivity analysis showed similar results.

The investigators found due to the presence of publication bias and low statistical power, elevated levels of blood homocysteine were not appreciably associated with risk of all-cause, vascular dementia and cognitive impairment without dementia.

The investigators concluded every 5 μmol/L increase in blood homocysteine is linearly associated with a 15% increase in relative risk of Alzheimer-type dementia.

Original title:
Hyperhomocysteinemia and risk of incident cognitive outcomes: An updated dose-response meta-analysis of prospective cohort studies by Zhou F and Chen S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30826501

Additional information of El Mondo:
Find more information/studies on Alzheimer disease.
 

Objectives:
Although intake of fruits and vegetables seemed to have a protective effect on bone metabolism, its effect on fractures remains uncertain. Therefore, this review article has been conducted.

Does intake of fruits and vegetables reduce risk of fractures?

Study design:
This review article included 6 cohort studies and 4 RCTs.
6 cohort studies included 225,062 participants (134,365 women and 90,697 men) aged 50 years or older. The participants’ follow-up time ranged from 2.8 years to 20 years.

Validated food frequency questionnaires (FFQs), 24-hour food recall (24h-R) and 7-day food record were used to evaluate fruit and vegetable intake.

Results and conclusions:
The investigators found in 5 cohort studies that intake of at least one serving of fruits and vegetables per day significantly reduced risk of hip fractures with 8% [pooled HR = 0.92, 95% CI = 0.87 to 0.98, I2 = 55.7%, p = 0.060] among participants aged 50 years or older.

The investigators found in 2 cohort studies that intake of at least one serving of fruits and vegetables per day significantly reduced risk of any fractures with 10% [pooled HR = 0.90, 95% CI = 0.86 to 0.96, I2 = 24.9%, p = 0.249] among participants aged 50 years or older.

The investigators found no association between the bone resorption marker CTx and 3 months of fruit and vegetable intake evaluated by 4 RCTs.

The investigators concluded that at least one serving of fruits and vegetables per day is associated with a lower risk of fractures among participants aged 50 years or older.

Original title:
Fruit and vegetable intake and bones: A systematic review and meta-analysis by Brondani JE, Comim FV, […], Premaor MO.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544223/

Additional information of El Mondo:
Find more information/studies on fruits and vegetables consumption and elderly.
 

Objectives:
Does a dietary low-ratio n-6/n-3 PUFA supplementation improve risk factors (such as fasting blood glucose, HbA1c) of diabetes?

Study design:
This review article included 11 RCTs.

No significant publication bias was observed for all blood glucose and other related indicators as suggested by Begg's test and Egger's test.

Results and conclusions:
The investigators found no significant effect of dietary low-ratio n-6/n-3 PUFA supplementation on:
-fasting blood glucose [WMD = 0.057 mmol/L, 95% CI = -0.090 to 0.204 mmol/L];
-insulin [WMD = -0.757 mIU/L, 95% CI = -2.419 to 0.904 mIU/L];
-insulin resistance index [WMD = -0.201, 95% CI = -0.566 to 0.165] and;
-glycosylated hemoglobin [WMD = -0.063%, 95% CI = -0.061 to 0.186%].

The investigators found subgroup analysis showed that the effect of dietary low-ratio n-6/n-3 PUFA on the reduction of the plasma insulin level in North America [WMD = -3.473 mIU/L, 95% CI = -5.760 to -1.185 mIU/L] was more obvious than that in Asian countries [WMD = -0.797 mIU/L, 95% CI = -2.497 to 0.902 mIU/L] and European countries [WMD = -0.063 mIU/L, 95% CI = -0.061 to 0.186 mIU/L].

The investigators found in the subgroup of diabetic subjects, dietary low-ratio n-6/n-3 PUFA supplementation significantly decreased plasma insulin level [WMD = -3.010 mIU/L, 95% CI = -5.371 to -0.648 mIU/L] and insulin resistance index [WMD = -0.460, 95% CI = -0.908 to -0.012].

The investigators found when the intervention period was longer than 8 weeks, dietary low-ratio n-6/n-3 PUFA supplementation significantly decreased the plasma insulin level [WMD = -2.782 mIU/L, 95% CI = -4.946 to -0.618 mIU/L].

The investigators concluded dietary low-ratio n-6/n-3 PUFA supplementation improves the glucose metabolism by reducing the insulin and insulin resistance in the diabetic patients. Dietary low-ratio n-6/n-3 PUFA supplementation also reduces the plasma insulin level when the supplementation duration is longer than 8 weeks.

Original title:
Effect of low-ratio n-6/n-3 PUFA on blood glucose: a meta-analysis by Li N, Yue H, […], Xu T.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31292599

Additional information of El Mondo:
Find more information/studies on diabetes and PUFA right here.

Objectives:
The associations between dietary fat intake and cognitive function are inconsistent and inconclusive. Therefore, this review article has been conducted.

Is there a relationship between different types of fat intake and cognitive impairment?

Study design:
This review article included 9 prospective cohort studies covering a total of 23,402 participants.

Results and conclusions:
The investigators found compared with the lowest category of consumption, the highest category of saturated fat consumption significantly increased risk of cognitive impairment with 40% [RR = 1.40, 95% CI = 1.02-1.91].

The investigators found compared with the lowest category of consumption, the highest category of saturated fat consumption significantly increased risk of Alzheimer disease with 87% [RR = 1.87, 95% CI = 1.09-3.20].

The investigators found total and unsaturated fat dietary intakes were not statistically associated with cognitive outcomes with significant between-study heterogeneity.

The investigators concluded there is an increased risk between saturated fat consumption and both cognitive impairment and Alzheimer disease. Given the substantial heterogeneity in the sample size and methodology used across studies, the evidence presented here should be interpreted with caution.

Original title:
Dietary Fat Intake and Cognitive Function among Older Populations: A Systematic Review and Meta-Analysis by Cao GY, Li M, […], Xu B.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31062836

Additional information of El Mondo:
Find more information/studies on saturated fat intake, dementia and elderly right here.

A diet with a high saturated fat intake is a diet with >10 En% saturated fat.
>10 En% saturated fat means that the total amounts of saturated fat make up for >10% of the total kcal of the diet.
The easiest way to follow this diet is to choose only meals/products that also contain 10 En% saturated fat.
Check here which products contain >10 En% saturated fat.

A diet with a low saturated fat intake is a diet with 7 En% saturated fat.

Objectives:
No conclusive information is available about the association between dietary total antioxidant capacity (DTAC) and risk of mortality. Therefore, this review article has been conducted.

Does dietary total antioxidant capacity (DTAC) reduce risk of death from all-cause (all-cause mortality), cancer (cancer mortality) and cardiovascular diseases (CVDs mortality)?

Study design:
This review article included 5 prospective cohort studies with a follow-up period of 4.3-16.5 years. There were 38,449 deaths from all-cause, 4,470 from cancer and 2,841 from cardiovascular diseases among 226,297 individuals.

Results and conclusions:
The investigators found dietary total antioxidant capacity significantly reduced all-cause mortality with 38% [combined effect size = 0.62, 95% CI = 0.60-0.64].
Significant because combined effect size of 1 was not found in the 95% CI of 0.60 to 0.64. Combined effect size of 1 means no risk/association.

The investigators found dietary total antioxidant capacity significantly reduced cancer mortality with 19% [combined effect size = 0.81, 95% CI = 0.75-0.88].
Significant means that there is an association with a 95% confidence.

The investigators found dietary total antioxidant capacity significantly reduced cardiovascular diseases mortality with 29% [combined effect size = 0.71, 95% CI = 0.63-0.82].

The investigators found findings from linear dose-response meta-analysis revealed that a 5 mmol/day increment in dietary total antioxidant capacity based on ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) was associated with 7% and 15% lower risk of all-cause mortality, respectively.

The investigators found findings from non-linear dose-response meta-analysis showed a significant reduction in risk of all-cause mortality when increasing ferric reducing antioxidant power (FRAP) from 2 to 12 mmol/day [p-nonlinearity = 0.002] and oxygen radical absorbance capacity (ORAC) from 5 to 11 mmol/day [p-nonlinearity  0.001].

The investigators concluded a diet with high total antioxidant capacity decreases risk of death from all-cause, cancer and cardiovascular diseases.

Original title:
Dietary total antioxidant capacity and mortality from all causes, cardiovascular disease and cancer: a systematic review and dose-response meta-analysis of prospective cohort studies by Parohan M, Anjom-Shoae J, […], Sadeghi O

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30756144

Additional information of El Mondo:
Find more information/studies on significantly/review article, antioxidant and cancer and cardiovascular diseases mortality right here.

The easiest way to get enough antioxidants from food is to eat at least 200 grams of vegetables and at least 200 grams of fruit per day.

There exist different methods to measure the antioxidant capacity of foods: Oxygen Radical Absorbance Capacity (ORAC), Ferric Ion Reducing Power (FRAP) and Trolox Equivalence Antioxidant Capacity (TEAC). The most popular method is the ORAC determination, which was developed by the National Institutes of Health in Baltimore.

The USDA recommends an ORAC unit ingestion of about 3000 to 5000 units daily.

Objectives:
Is there an association between potato consumption and risk of all-cause, cancer and cardiovascular mortality in adults?

Study design:
This review article included 20  prospective cohort studies with 25,208 cases of all-cause mortality, 4,877 of cancer mortality and 2,366 of cardiovascular mortality.

There was no evidence for publication bias.

Results and conclusions:
The investigators found no significant association between potato consumption and risk of all-cause [RR = 0.90, 95% CI = 0.8 to 1.02, p = 0.096] and cancer [RR = 1.09, 95% CI = 0.96 to 1.24, p = 0.204] mortality.

The investigators found, in addition, no significant linear association between each 100 g/d increments in potato consumption and risk of all-cause [p = 0.7] and cancer [p = 0.09] mortality.
Moreover, nonlinear association between potato consumption and risk of cancer mortality was non-significant [p-nonlinearity = 0.99].

The investigators found, in addition, 2 of 3 studies which examined the association of potato consumption with cardiovascular mortality did not find any significant relationship.

The investigators concluded there is no association between potato consumption and risk of all-cause, cancer and cardiovascular mortality in adults.

Original title:
Potato consumption and risk of all cause, cancer and cardiovascular mortality: a systematic review and dose-response meta-analysis of prospective cohort studies by Darooghegi Mofrad M, Milajerdi A, […], Azadbakht L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30638040

Additional information of El Mondo:
Find more information/studies on of potato consumption and elderly right here.
 

Objectives:
Existing studies suggest that dietary vitamins and carotenoids might be associated with a reduced risk of age-related cataract (ARC), although a quantitative summary of these associations is lacking. Therefore, this review article has been conducted.

Do vitamins and carotenoids intake reduce risk of the eye disease age-related cataract? 

Study design:
This review article included 8 RCTs and 12 cohort studies.

Results and conclusions:
The investigators found in cohort studies a significantly reduced risk of 19% [RR = 0.81, 95% CI = 0.71 to 0.92, p = 0.001] of age-related cataract for dietary vitamin A intake.

The investigators found in cohort studies a significantly reduced risk of 20% [RR = 0.80, 95% CI = 0.72 to 0.88, p 0.001] of age-related cataract for dietary vitamin C intake.

The investigators found in cohort studies a significantly reduced risk of 10% [RR = 0.90, 95% CI = 0.80 to 1.00, p 0.049] of age-related cataract for dietary vitamin E intake.

The investigators found in cohort studies a significantly reduced risk of 10% [RR = 0.90, 95% CI = 0.83 to 0.99, p = 0.023] of age-related cataract for dietary β-carotene intake.

The investigators found in cohort studies a significantly reduced risk of 19% [RR = 0.81, 95% CI = 0.75 to 0.89, p 0.001] of age-related cataract for dietary β lutein or zeaxanthin intake.

The investigators found in RCTs compared with the placebo, a non-significantly reduced risk of 3% [RR = 0.97, 95% CI = 0.91 to 1.03, p 0.262] of age-related cataract for vitamin E supplementation.
Non-significantly because RR of 1 was found in the 95% CI of 0.91 to 1.03. RR of 1 means no risk/association.

The investigators found in RCTs compared with the placebo, a non-significantly reduced risk of 1% [RR = 0.99, 95% CI = 0.92 to 1.07, p 0.820] of age-related cataract for β-carotene supplementation.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 26% [RR = 0.74, 95% CI = 0.67 to 0.80, p 0.001] of age-related cataract for every 10-mg/d increase in dietary lutein or zeaxanthin intake.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 18% [RR = 0.82, 95% CI = 0.74 to 0.91, p 0.001] of age-related cataract for every 500-mg/d increase in dietary vitamin C intake.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 8% [RR = 0.92, 95% CI = 0.88 to 0.96, p 0.001] of age-related cataract for every 5-mg/d increase in dietary β-carotene intake.

The investigators found in dose-response analysis of cohort studies a significantly reduced risk of 6% [RR = 0.94, 95% CI = 0.90 to 0.98, p 0.001] of age-related cataract for every 5 mg/d increase in dietary vitamin A intake.

The investigators concluded dietary intake of vitamin A (at least 5 mg per day), vitamin C (at least 500 mg per day), vitamin E, β-carotene (at least 5 mg per day) and lutein or zeaxanthin intake (at least 10 mg per day) reduce risk of age-related cataract.

Original title:
Dietary vitamin and carotenoid intake and risk of age-related cataract by Jiang H, Yin Y, […], Ma L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30624584

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Find more information/studies on of vitamin A, vitamin C, vitamin E, β-carotene and elderly right here.
 

Objectives:
Several studies have been conducted on the relationship between tea intake and the risk of osteoporosis. The results from these studies are, however, inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does tea intake reduce risk of osteoporosis?

Study design:
This review article included 2 prospective cohort studies, 4 cross-sectional studies and 11 case-control studies with 107,819 cases (people with osteoporosis). In the present study, the main symptom of osteoporosis was hip fracture.
10 studies - case-control and cohort studies were all of high quality - were in relative high quality (over 6 stars) with an average NOS score of 7.23.

The heterogeneity in the present review article mainly came from Asia group, female group, prospective cohort study group and case-control study group.

There was no publication bias of the meta-analysis about tea consumption and osteoporosis.

Results and conclusions:
The investigators found for the highest versus the lowest categories of tea consumption a significantly reduced risk of 38% [total OR = 0.62, 95% CI = 0.46-0.83, I2  =  94%, p   0 .01] for osteoporosis. However, when reducing heterogeneity, the overall OR [95% CI = 0.57-0.74, I2 = 30%] was still significant.
Subgroup analysis showed that tea consumption significantly reduced the risk of osteoporosis in all examined subgroups.

The investigators found stratified by categories of osteoporosis, a significantly reduced risk of 26% [OR  =  0.74, 95% BI = 0.63-0.88] for hip fracture.

The investigators found among women a significantly reduced risk of 27% [OR  =  0.73, 95% CI = 0.54-0.99] for osteoporosis.

The investigators concluded that high tea consumption reduces risk of osteoporosis, particularly hip fracture and particularly among women. However, the exact mechanism of the relationship between tea consumption and osteoporosis still needs further research.

Original title:
Association between tea consumption and osteoporosis: A meta-analysis by Sun K, Wang L, [...], Li X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5728912/

Additional information of El Mondo:
Find more information/studies on tea consumption and elderly right here.
 

Objectives:
Previous studies have shown that fish consumption and dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs) are associated with hip fracture; however, findings were conflicting. Therefore, this review article (meta-analysis) has been conducted.

Do both dietary intake of fish and n-3 polyunsaturated fatty acids decrease hip fracture risk?

Study design:
This review article included 7 prospective cohort studies and 3 case-control studies with a total sample size of 29,2657 participants. The age of participants was 20 years or older.

Results and conclusions:
The investigators found combining 8 effect sizes from 4 prospective cohort studies and 2 case-control studies revealed a significant inverse association between fish consumption and risk of hip fracture [pooled effect size = 0.88, 95% CI = 0.79-0.98, p = 0.02].
Although this relationship became non-significant in prospective cohort studies, a significant inverse association was found in prospective cohort studies with sample size of 10,000 individuals or more and studies that considered body mass index as a covariate.

The investigators also found dietary intake of n-3 PUFAs significantly reduced risk of hip fracture with 12% [pooled effect size = 0.88, 95% CI = 0.80-0.98, p = 0.02].

The investigators concluded that both fish consumption and dietary intake of n-3 PUFAs have protective effects on bone health and decline the risk of hip fracture.

Original title:
Dietary intake of fish, n-3 polyunsaturated fatty acids and risk of hip fracture: A systematic review and meta-analysis on observational studies by Sadeghi O, Djafarian K, […], Shab-Bidar S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29244536

Additional information of El Mondo:
Find more information/studies on fish consumption, n-3 PUFAs and elderly right here.

Fatty acids in fish are all n-3 PUFAs.
 

Objectives:
There is considerable evidence of the favourable role of more physical activity (PA) in fighting against dementia. However, the shape of the dose-response relationship is still unclear. Therefore, this review article (meta-analysis) has been conducted.

Does leisure time physical activity reduce risk of all-cause dementia (ACD), Alzheimer’s disease (AD) and vascular dementia (VD) in dose-response manner?

Study design:
This review article included 15 cohort studies with 37,436 participants for all-cause dementia, with 25,031 participants for Alzheimer’s disease and with 16,797 participants for vascular dementia.
During follow-up (3-31.6 years for all-cause dementia, 3.9-31.6 years for Alzheimer’s disease and 4-11.9 years for vascular dementia), at least 2,665, 1,337 and 343 participants who were not suffering from dementia at baseline (=at the beginning of the study) were diagnosed with all-cause dementia, Alzheimer’s disease and vascular dementia, respectively.

There was no publication bias.

Results and conclusions:
The investigators found in the dose-response analysis, either all-cause dementia [p trend 0.005 and p non-linearity = 0.87] or Alzheimer’s disease [p trend 0.005 and p non-linearity = 0.10] exhibited a linear relationship with leisure time physical activity over the observed range (0-2000 kcal/week or 0-45 metabolic equivalent of task hours per week (MET-h/week)).

The investigators found for every 500 kcal or 10 MET-h increase per week, a significantly 10% [95% CI = 0.85-0.97] and 13% [95% CI = 0.79-0.96] decrease in the risk of all-cause dementia and Alzheimer’s disease, respectively.

The investigators concluded leisure time physical activity over a specific range (0-2000 kcal/week or 0-45 MET-h/week) is associated with a risk of dementia and Alzheimer’s disease in an inverse linear dose-response manner; with for every 500 kcal (calories) or 10 MET-h increase per week, a 10% and 13% decrease in the risk of all-cause dementia and Alzheimer’s disease, respectively.

Original title:
Leisure time physical activity and dementia risk: a dose-response meta-analysis of prospective studies by Xu W, Wang HF, [...], Tan L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5665289/

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If you do a 4 MET activity for 30 minutes, you have done 4 x 30 = 120 MET-minutes or 2.0 MET-hours of physical activity.
 

Objectives:
The aim of this meta-analysis (review article) is to evaluate the influence of dietary intake and blood level of vitamin A (total vitamin A, retinol or β-carotene) on total and hip fracture risk?

Study design:
This review article included 11 prospective cohort studies and 2 nested case-control studies, involving a total of 319,077 participants over the age of 20 years (109,056 post-menopausal women).

Results and conclusions:
The investigators found higher dietary intake of retinol significantly decreased total fracture risk with 5% [RR = 0.95, 95% CI = 0.91 to 1.00, I2 = 64.64%, p = 0.04].

The investigators found higher dietary intake of retinol significantly increased hip fracture risk with 40% [RR = 1.40, 95% CI = 1.02 to 1.91, I2 = 30.01%, p = 0.40].

The investigators found higher dietary intake of vitamin A significantly decreased total fracture risk with 6% [RR = 0.94, 95% CI = 0.88 to 0.99, I2 = 35.18%, p = 0.20].

The investigators found higher dietary intake of vitamin A significantly increased hip fracture risk with 29% [RR = 1.29, 95% CI = 1.06 to 1.57, I2 = 0.00%, p = 0.60].

The investigators found lower blood level of retinol significantly increased hip fracture risk with 27% [RR = 1.27, 95% CI = 1.05 to 1.53, I2 = 0.00%, p = 0.62].

The investigators concluded that higher dietary intake of total vitamin A or retinol increases the risk of hip fracture but decreases total fracture risk. Clinical trials are warranted to confirm these results and assess the clinical applicability.

Original title:
The Effect of Vitamin A on Fracture Risk: A Meta-Analysis of Cohort Studies by Zhang X, Zhang R, [...], Chen G.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615580/

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Vitamin A is a generic term for compounds with the biological activity of retinol. Preformed vitamin A (mainly retinol and retinyl esters) is usually found in foods derived from animal products and provitamin A (mainly β-carotene and carotenoids) is usually found in foods derived from plant products.
 

Objectives:
Vitamin D is involved in musculoskeletal health. There is no consensus on a possible association between circulating 25-hydroxyvitamin D (25OHD) concentrations and walking speed, a “vital sign” in older adults. Therefore, this meta-analysis (review article) has been conducted.

Does a high vitamin D level (expressed as circulating 25-hydroxyvitamin D (25OHD) concentrations) increase walking speed in older adults?

Study design:
This review article included 22 observational studies (17 cross-sectional and 5 longitudinal). The number of participants ranged between 54 and 4,100 (0-100% female).

Results and conclusions:
The investigators found usual walking speed was slower among participants with hypovitaminosis D, with a clinically relevant difference compared with normal vitamin D (>75 nmol/L) of -0.18m/s for severe vitamin D deficiency (≤25 nmol/L), -0.08m/s for vitamin D deficiency (≤50 nmol/L) and -0.12m/s for vitamin D insufficiency (≤75 nmol/L).

The investigators found similar results regarding the fast walking speed [mean differences = -0.04m/s for vitamin D deficiency (≤50 nmol/L) and vitamin D insufficiency (≤75 nmol/L) compared with normal vitamin D (>75 nmol/L) and Timed Up and Go test (TUG) [mean difference = 0.48s for severe vitamin D deficiency (≤25 nmol/L) compared with normal vitamin D (>75 nmol/L).

The investigators found a slow usual walking speed was positively associated with:
-severe vitamin D deficiency (≤25 nmol/L) [summary OR = 2.17, 95% CI = 1.52-3.10];
-vitamin D deficiency (≤50 nmol/L) [OR = 1.38, 95% CI = 1.01-1.89] and;
-vitamin D insufficiency (≤75nmol/L) [OR = 1.38, 95% CI = 1.04-1.83], using normal vitamin D (>75 nmol/L) as the reference.

The investigators concluded that robust evidence shows a high 25OHD concentration (vitamin D level of >75 nmol/L) increases walking speed among older adults.

Original title:
Vitamin D and walking speed in older adults: Systematic review and meta-analysis by Annweiler C, Henni S, [...], Duval GT.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29150169

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A vitamin D level of >75 nmol/L can be achieved by taking 800-1200 IU/d (800-1200 mcg/d) vitamin D3 supplements.
 

Objectives:
No quantitative assessment has been performed to specifically link the consumption of fruit and vegetables with the incident risk of cognitive disorders. Therefore, this meta-analysis (review article) has been conducted.

Does consumption of fruit and vegetables reduce risk of cognitive disorders?

Study design:
This review article included 6 cohort studies involving a total of 21,175 participants.

Results and conclusions:
The investigators found in pooled analysis that consumption of fruit and vegetables significantly reduced risk of cognitive disorders with 26% [pooled RR = 0.74, 95% BI = 0.62-0.88, I2 = 68%; the significant heterogeneity might be attributed to the ethnic difference].

The investigators concluded that consumption of fruit and vegetables reduces risk of cognitive disorders. However, further large prospective studies should be performed to quantify the potential dose-response patterns of fruit and/or vegetables intake and to explore the role of fruit or vegetables consumption separately on cognitive disorders in different populations.

Original title:
Intake of Fruit and Vegetables and the Incident Risk of Cognitive Disorders: A Systematic Review and Meta-Analysis of Cohort Studies by Wu L, Sun D and Tan Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29188891

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Objectives:
Currently, dementia is considered untreatable and there are many factors that cause dementia. However, previous studies were unable to identify the factors that affect directly. Therefore, this meta-analysis (review article) has been conducted.

What are the risk factors for prognostic dementia in stroke patients?

Study design:
This review article included 7 hospital-based cohorts of consecutive patients with stroke and 1 population-based cross-sectional study.

Results and conclusions:
The investigators found:
a significantly increased risk of 68% [pooled relative ratio = 1.68, 95% CI = 1.28 to 2.22, I2 = 72%] for atrial fibrillation;
a significantly increased risk of 59% [pooled relative ratio = 1.59, 95% CI = 1.33 to 1.91] for previous stroke;
a significantly increased risk of 40% [pooled relative ratio = 1.40, 95% CI = 1.23 to 1.59, I2% = 14%] for myocardial infarction;
a significantly increased risk of 36% [pooled relative ratio = 1.36, 95% CI = 1.20 to 1.53, I2 = 46%] for hypertension;
a significantly increased risk of 25% [pooled relative ratio = 1.25, 95% CI = 1.11 to 1.41, I2 = 0%] for diabetes mellitus and;
a significantly increased risk of 25% [pooled relative ratio = 1.25, 95% CI = 1.08 to 1.45, I2 = 16%] for previous transient ischemic attack (TIA).

The investigators concluded that strongly risk factors associated with increased risk of post-stroke dementia are atrial fibrillation, previous stroke, myocardial infarction, hypertension, diabetes and previous TIA. However, there are other risk factors related to dementia. Therefore, further studies are needed to investigate and develop the risk score value to forecast the dementia incident in stroke patients.

Original title:
Risk factors associated with post-stroke dementia: a systematic review and meta-analysis by Surawan J, Areemit S, […], Saensak S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5641826/

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Objectives:
Whole grains are rich source of nutrients and have shown beneficial effects on human health. Therefore, this meta-analysis (review article) has been conducted.

Do taking whole grains reduce mortality risk?

Study design:
This review article included 19 cohort studies with in total 1,041,692 participants and 96,710 deaths.

Results and conclusions:
The investigators found when comparing the highest versus the lowest categories of whole grain, a significantly reduced risk of 16% [RR = 0.84, 95% CI = 0.81-0.88, n = 9] for total mortality.

The investigators found when comparing the highest versus the lowest categories of whole grain, a significantly reduced risk of 17% [RR = 0.83, 95% CI = 0.79-0.86, n = 8] for cardiovascular mortality.

The investigators found when comparing the highest versus the lowest categories of whole grain, a non-significantly reduced risk of 6% [RR = 0.94, 95% CI = 0.87-1.01, n = 14] for cancer mortality.

The investigators found a nonlinear relationship of whole grain intake with risk of total, cardiovascular and cancer mortality.

The investigators found each 28 g/d intake of whole grains was associated with a 9% [pooled RR = 0.91, 95% CI = 0.90-0.93] lower risk for total mortality.

The investigators found each 28 g/d intake of whole grains was associated with a 14% [pooled RR = 0.86, 95% CI = 0.83-0.89] lower risk for cardiovascular mortality.

The investigators found each 28 g/d intake of whole grains was associated with a 3% [pooled RR = 0.97, 95% CI = 0.95-0.99] lower risk for cancer mortality.

The investigators concluded that a higher whole grain intake (at least 28 g/d) reduces risk of total, cardiovascular and cancer mortality. These findings support current dietary guidelines to increase the intake of whole grains. Government officials, scientists and medical staff should take actions to promote whole grains intake.
 
Original title:
Association of whole grain intake with all-cause, cardiovascular, and cancer mortality: a systematic review and dose-response meta-analysis from prospective cohort studies by Zhang B, Zhao Q, [...], Wang X.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29091078

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Objectives:
Previous studies had inconsistent findings regarding the association between vitamin C intake and the risk of hip fracture. Therefore, this meta-analysis (review article) has been conducted.

Does taking dietary vitamin C reduce risk of hip fracture?

Study design:
This review article included 6 articles, containing 7908 controls and 2899 cases of hip fracture.

Results and conclusions:
The investigators found when comparing the highest versus the lowest categories of vitamin C, that dietary vitamin C was statistically correlated with a lower risk of 27% for hip fracture [overall OR = 0.73, 95% CI = 0.55-0.97, I2 = 69.1%].

The investigators found that every increment of 50 mg/day dietary vitamin C intake significantly reduced risk of hip fracture with 5% [OR = 0.95, 95% CI = 0.91-1.00, p = 0.05].

The investigators concluded that increasing dietary vitamin C (at least 50 mg/day) intake decreases the risk of hip fracture. In order to verify the association of vitamin C intake and hip fracture risk, further well-designed largely randomized controlled trials (RCTs) are needed.

Original title:
Dietary vitamin C intake and the risk of hip fracture: a dose-response meta-analysis by Sun Y, Liu C, […], Lu Q.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29101410

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Objectives:
Fish are a primary source of long-chain omega-3 fatty acids, which may help delay cognitive aging. Therefore, this meta-analysis (review article) has been conducted.

Does a higher fish intake reduce cognitive decline?

Study design:
This review article included 5 cohort studies (23,688 Caucasians aged ≥65 years, 88% female and median follow-up range of 3.9-9.1 years).

Results and conclusions:
The investigators found in multivariate analyses, higher fish intake was associated with slower decline in both global cognition and memory [p-trend ≤ 0.031].

The investigators found consuming ≥4 versus 1 fish serving/week was associated with 0.018 [95% CI = 0.004-0.032] standard units lower rate of memory decline; an effect estimate equivalent to that found for 4 years of age.

The investigators found for global cognition, no comparisons of higher versus low fish intake reached statistical significance.

The investigators found no evidence of effect modification by Alzheimer's.

The investigators concluded that increasing fish intake (at least 4 servings/week) is associated with decreasing memory decline of older persons.

Original title:
Fish intake, genetic predisposition to alzheimer's disease and decline in global cognition and memory in five cohorts of older persons by Samieri C, Morris MC,[…], Grodstein F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29053784

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A typical serving size of fish can range from 3 to 6 oz., depending on the type of fish and its preparation. The American Heart Association considers 3.5 oz. of cooked fish, or about 3/4 cup, to be a single serving.
 

Objectives:
With an aging population and no cure for dementia on the horizon, risk factor modification prior to disease onset is an urgent health priority. Therefore, this meta-analysis (review article) has been conducted.

What is the effect of low vitamin D status or vitamin D supplementation on cognition in midlife and older adults without a diagnosis of dementia?

Study design:
This review article included 26 observational (cross-sectional and longitudinal cohort) studies and 3 intervention studies (n = 19-9,556).

Results and conclusions:
The investigators found in 26 observational studies that low vitamin D status was associated with worse cognitive performance [OR = 1.24, CI = 1.14-1.35] and cognitive decline [OR = 1.26, CI = 1.09-1.23] in midlife and older adults without a diagnosis of dementia; with cross-sectional yielding a stronger effect compared to longitudinal studies.

However, the investigators found in 3 intervention studies that vitamin D supplementation showed no significant benefit on cognition compared with control [SMD = 0.21, CI = -0.05 to 0.46].

The investigators concluded that observational evidence demonstrates low vitamin D is related to poorer cognition in midlife and older adults without a diagnosis of dementia; however, interventional studies are yet to show a clear benefit from vitamin D supplementation. From the evidence to date, there is likely a therapeutic age window relevant to the development of disease and therefore vitamin D therapy. Longitudinal lifespan studies are necessary to depict the optimal timing and duration in which repletion of vitamin D may protect against cognitive decline and dementia in aging, to better inform trials and practice towards a successful therapy.

Original title:
A Systematic Review and Meta-Analysis of The Effect of Low Vitamin D on Cognition by Goodwill AM and Szoeke C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28758188

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