Nutrition and health

Objectives:
Recent evidence suggests that diet can modify the risk of future cognitive impairment and dementia. A biologically plausible rationale and initial clinical data indicate that the antioxidant activities of dietary carotenoids may assist the preservation of cognitive function. Therefore, this review article has been conducted.

Does carotenoid supplementation improve cognitive performance among healthy adults?

Study design:
This review article included 9 RCTs, involving 2,228 subjects in the treated group (group with carotenoid supplementation) and 2,174 subjects in control group (group without carotenoid supplementation).
The age of all participants varied from 45 to 78 years.
The majority of clinical trials assessed the effect of xanthophylls such as lutein, zeaxanthin, and astaxanthin, whereas only 1 study determined the effects of β-carotene.
The duration of carotenoid supplementation ranged from 2 weeks to 12 months.
The dosage of carotenoids administered in the studies ranged from 0.5 mg/d to 50 mg/d.
There was no evidence of publication bias.

Results and conclusions:
The investigators found results of the pooled meta-analysis showed a significant effect of carotenoid intervention on cognitive outcomes [Hedge's g = 0.14, 95% CI = 0.08 to 0.20, p 0.0001, I2 = 0.00%].
The sensitivity analysis did not change the overall findings obtained from the primary analysis.

The investigators concluded that these results highlight the potential role of carotenoids (0.5 mg/d to 50 mg/d) in the protection of mental functions even in subjects (healthy participants aged 45-78 years) without cognitive impairment. This is particularly important because the population is aging and preservation of cognitive function is crucial for individual autonomy and quality of life, even in non-demented subjects. Further well-powered and long-term trials are required to determine treatment duration, type of carotenoid and optimal dosage.

Original title:
Carotenoids and Cognitive Outcomes: A Meta-Analysis of Randomized Intervention Trials by Davinelli S, Ali S, […], Corbi G.

Link:
https://www.mdpi.com/2076-3921/10/2/223/htm

Additional information of El Mondo:
Find more information/studies on carotenoids and dementia right here.
 

Objectives:
Increasing macular pigment optical density (MPOD) as a result of increased macular concentration of lutein and zeaxanthin may reduce the risk of age-related macular degeneration (AMD). Therefore, this review article has been conducted.

Have daily egg consumption beneficial effects on macular pigment optical density and serum lutein levels?

Study design:
This review article included 5 RCTs with a total of 296 participants.
There was no heterogeneity between studies.

Results and conclusions:
The investigators found that egg consumption significantly increased macular pigment optical density [WMD = +0.037, 95% CI = 0.004 to 0.069, p = 0.027] and serum lutein levels [WMD = +0.150 μmol/L, 95% CI = 0.037 to 0.263, p = 0.009].

The investigators found subgroup analyses showed that egg consumption had a larger effect on macular pigment optical density in studies with a parallel design and increased serum lutein levels to a greater extent in a healthy population.

The investigators concluded daily egg consumption have beneficial effects on macular pigment optical density and serum lutein level is inversely associated with reduced age-related macular degeneration progression. Further clinical trials are required to confirm the results of this review article.

Original title:
A positive effect of egg consumption on macular pigment and healthy vision: a systematic review and meta-analysis of clinical trials by Sikaroudi MK, Saraf-Bank S, […], Soltani S.

Link:
https://pubmed.ncbi.nlm.nih.gov/33491232/

Additional information of El Mondo:
Find here more information/studies about review article/significant, egg consumption and elderly diseases.
 

Objectives:
Does a high dietary intake of β-cryptoxanthin reduce the risk of osteoporosis and hip fracture?

Study design:
This review article included 7 cohort studies, 4 case-control studies and 4 cross-sectional studies with a total of 100,496 individuals.
The methodological qualities of all studies were rated as “fair” to “good”.
The number of populations in each study ranged from 59 to 25,566.

Results and conclusions:
The investigators found that a high dietary intake of β-cryptoxanthin significantly reduced risk of osteoporosis with 24% [OR = 0.76, 95% CI = 0.66 to 0.88, p = 0.0002, I2 = 36%, p = 0.11].

The investigators found in subgroup analysis that a high dietary intake of β-cryptoxanthin significantly reduced risk of osteoporosis with 28% [OR = 0.72, 95% CI = 0.58 to 0.91, p = 0.005, I2 = 59%] among women.

The investigators found in subgroup analysis that a high dietary intake of β-cryptoxanthin significantly reduced risk of osteoporosis with 20% [OR = 0.80, 95% CI = 0.65 to 1.00, p = 0.005, I2 = 11%] among men.

The investigators found that a high dietary intake of β-cryptoxanthin significantly reduced risk of hip fracture with 28% [OR = 0.72, 95% CI = 0.60 to 0.87, p = 0.0008, I2 = 55%].

The investigators found in subgroup analysis that a high dietary intake of β-cryptoxanthin significantly reduced risk of hip fracture with 29% [OR = 0.71, 95% CI = 0.54 to 0.94, p = 0.02, I2 = 71%] among women. 

The investigators concluded that a high dietary intake of β-cryptoxanthin reduces the risk of osteoporosis and hip fracture. Further longitudinal studies are needed to validate the causality of current findings.

Original title:
Effects of β-Cryptoxanthin on Improvement in Osteoporosis Risk: A Systematic Review and Meta-Analysis of Observational Studies by Kim SJ, Anh NH, […], Kwon SW.

Link:
https://www.mdpi.com/2304-8158/10/2/296/htm

Additional information of El Mondo:
Find more information/studies on β-cryptoxanthin and osteoporosis right here.
 

Objectives:
Do omega-3 fatty acid supplements (EPA and DHA) improve sarcopenia-related performances among the elderly?

Study design:
This review article included 10 RCTs with 552 participants.
The number of study participants ranged from 24 to 126 and the durations of the interventions spanned 10 to 24 weeks.
The doses ranged from 0.16 to 2.6 g/day of EPA and from 0 to 1.8 g/day of DHA.
The mean ages of the participants across the RCTs ranged from 63 to 75 years old.

Results and conclusions:
The investigators found in subgroup analyses that omega-3 fatty acid supplements (EPA and DHA) at more than 2 g/day significantly increased muscle mass among the elderly [SMD = 0.67 kg, 95% CI = 0.16 to 1.18, p 0.05].

The investigators found in subgroup analyses that omega-3 fatty acid supplements (EPA and DHA) during more than 6 months significantly improved walking speed among the elderly [SMD = 1.78 m/sec, 95% CI = 1.38 to 2.17, p 0.05].

The investigators concluded that taking at least 2 grams of omega-3 supplements (EPA and DHA) per day increases muscle mass among the elderly, while taking omega-3 supplements for at least 6 months increases walking speed among the elderly.

Original title:
Effects of Omega-3 Fatty Acids on Muscle Mass, Muscle Strength and Muscle Performance among the Elderly: A Meta-Analysis by Huang YH, Chiu WC, […], Wang YH.

Link:
https://www.mdpi.com/2072-6643/12/12/3739/htm

Additional information of El Mondo:
Find more information/studies on EPA and DHA consumption and elderly right here.
EPA and DHA are present in fish.
 

Objectives:
Does calcium combined with vitamin D supplementation reduce risk of osteoporosis in postmenopausal women?

Study design:
This review article included 10 RCTs.

Results and conclusions:
The investigators found calcium combined with vitamin D supplementation significantly increased total bone mineral density [SMD = 0.537, 95% CI = 0.227 to 0.847] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly increased lumbar spine bone mineral density [SMD = 0.233, 95% CI = 0.073 to 0.392, p 0.001] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly increased arms bone mineral density [SMD = 0.464, 95% CI = 0.186 to 0.741] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly increased femoral neck bone mineral density [SMD = 0.187, 95% CI = 0.010 to 0.364] in postmenopausal women.

The investigators found calcium combined with vitamin D supplementation significantly reduced risk of hip fracture with 13.6% [RR = 0.864, 95% CI = 0.763 to 0.979] in postmenopausal women.

The investigators found in subgroup analysis that calcium combined with 400 IU/d (10 mcg/d) vitamin D supplementation significantly increased femoral neck bone mineral density [SMD = 0.335, 95% CI = 0.113 to 0.558] in postmenopausal women.

The investigators found in subgroup analysis that dairy products fortified with calcium and vitamin D significantly increased total bone mineral density [SMD = 0.784, 95% CI = 0.322 to 1.247] in postmenopausal women.

The investigators found in subgroup analysis that dairy products fortified with calcium and vitamin D significantly increased lumbar spine bone mineral density [SMD = 0.320, 95% CI = 0.146 to 0.494] in postmenopausal women.

The investigators concluded that dairy products fortified with calcium and vitamin D have a favourable effect on bone mineral density. Furthermore, calcium combined with vitamin D supplementation could prevent osteoporosis hip fracture in postmenopausal women.

Original title:
Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials by Liu C, Kuang X […], Li D.

Link:
https://pubmed.ncbi.nlm.nih.gov/33237064/

Additional information of El Mondo:
Find more information/studies on dairy products consumption, calcium and vitamin D right here.

Objectives:
Isoflavones have a structure similar to 17β-estradiol, so they may be useful to postmenopausal women in preventing bone loss related to estrogen deficiency. Therefore, this review article has been conducted.

Do isoflavone supplements increase bone mineral density (BMD) in postmenopausal women?

Study design:
This review article included 63 RCTs, involving 6,427 postmenopausal women.

Isoflavone interventions were generally safe and well tolerated.

Results and conclusions:
The investigators found statistically significant differences in bone mineral density at the last follow-up visit between the two groups (isoflavones vs. control) at the lumbar spine [MD = 21.34 mg/cm², 95% CI = 8.21 to 34.47 mg/cm², p = 0.001], the femoral neck [MD = 28.88 mg/cm², 95% CI = 15.05 to 42.71 mg/cm², p 0.0001] and the distal radius [MD = 19.27 mg/cm², 95% CI = 5.65 to 32.89 mg/cm², p = 0.006].
This improved bone mineral density was found for genistein 54 mg/day and ipriflavone (a synthetic isoflavone) 600 mg/day.

The investigators concluded isoflavone interventions, genistein (54 mg/day) and ipriflavone (600 mg/day) in particular, have beneficial effects on bone mineral density outcomes and are safe in postmenopausal women. They may be considered as a complementary or alternative option in the prevention and treatment of menopause-related osteoporosis.

Original title:
Effects of Isoflavone Interventions on Bone Mineral Density in Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials by Sansai K, Takuathung MN, [...], Koonrungsesomboon N.

Link:
https://pubmed.ncbi.nlm.nih.gov/32524173/

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

Objectives:
Has oral supplementation of vitamin B (vitamins B1, B6, B12 and folic acid alone or combined) preventive effect on cognitive decline in cognitively unimpaired individuals?

Study design:
This review article included 20 RCTs, ranging from 23 to 2,919 participants per study, with a total of 12,697 participants.
8 of these 20 RCTs were deemed appropriate for the meta-analysis.

Results and conclusions:
The investigators found meta-analysis did not yield a significant overall effect of supplementation with vitamin B on cognitive function [SMD = 0.02, 95% CI = -0.034 to 0.08]. A sensitivity analysis focusing on specific risk factors did not alter this result.
Some studies reported isolated significant effects of the intervention on secondary outcomes. However, these findings were outnumbered by the number of cognitive tests that did not yield significant effects.

The investigators concluded there is no overall evidence that oral vitamin B supplementation prevent cognitive decline in cognitively unimpaired individuals. The results of this review do not provide evidence that population groups with certain risk factors would profit more from the intervention than others.

Original title:
Vitamin B-Can It Prevent Cognitive Decline? A Systematic Review and Meta-Analysis by Behrens A, Graessel E, [...], Donath C.

Link:
https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-020-01378-7

Additional information of El Mondo:
Find more information/studies on vitamins B1, B6, B12 and folic acid and dementia right here.

Objectives:
Previous studies did not draw a consistent conclusion about the effects of vitamin K combined with vitamin D on human skeletal quality. Therefore, this review article has been conducted.

Does vitamin K combined with vitamin D supplementation increase bone mineral density (BMD)?

Study design:
This review article included 8 RCTs with a total of 971 participants.

Results and conclusions:
The investigators found vitamin K combined with vitamin D supplementation significantly increased total bone mineral density (BMD) [pooled effect size = 0.316, 95% CI = 0.031 to 0.601].

The investigators found vitamin K combined with vitamin D supplementation significantly decreased levels of undercarboxylated osteocalcin [effect size = -0.945, 95% CI = -1.113 to -0.778].

The investigators found simultaneously, subgroup analysis showed that K2 or vitamin K (not specified) supplement less than 500 μg/d, when combined with vitamin D significantly increased total bone mineral density compared with the control group fed a normal diet or the group with no treatment [effect size = 0.479, 95% CI = 0.101 to 0.858 and effect size = 0.570, 95% CI = 0.196 to 0.945, respectively).

The investigators concluded the combination of vitamin K and D supplement increases the total bone mineral density (BMD) and decreases levels of undercarboxylated osteocalcin and a more favorable effect is expected when less than 500 μg/d vitamin K2 is used.

Original title:
The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials by Kuang X, Liu C, […], Li D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32219282

Additional information of El Mondo:
Find more information/studies on elderly, vitamin D and K right here.

Undercarboxylated osteocalcin represents inadequately carboxylated osteocalcin and this fraction increases with vitamin K insufficiency.

Objectives:
Is there a causal relationship between dietary intake of dairy products and a positive effect on bone mineral density (BMD) in healthy postmenopausal women?

Study design:
This review article included 6 RCTs with a total of 618 participants. Milk was the main dairy product used in the trials.

Results and conclusions:
The investigators found there was a significant association between dairy product consumption and bone mineral density of the lumbar spine [SMD = 0.21, 95% CI = 0.05 to 0.37, p = 0.009], femoral neck [SMD = 0.36, 95% CI = 0.19 to 0.53, p  0.001], total hip [SMD = 0.37, 95% CI = 0.20 to 0.55, p  0.001] and total body [SMD = 0.58, 95% CI = 0.39 to 0.77, p  0.001].

The investigators found subgroup analysis showed a positive effect of dairy product consumption on the bone mineral density of the total hip starting from 12 months and the femoral neck starting from 18 months. There was also a positive association with the bone mineral density in the 4 sites in people living in low-calcium intake countries.

The investigators concluded that there is a causal relationship between dietary intake of dairy products, particularly milk during at least 12 months and a positive effect on bone mineral density (BMD) in healthy postmenopausal women. Therefore, dairy product consumption should be considered an effective public health measure to prevent osteoporosis in postmenopausal women.

Original title:
Effects of dairy products on bone mineral density in healthy postmenopausal women: a systematic review and meta-analysis of randomized controlled trials by Shi Y, Zhan Y, [...], Jiang Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32185512

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

Menopause is the point when a woman no longer has menstrual periods for at least 12 months. Postmenopause is the stage after menopause.

Objectives:
Does a high LDL cholesterol level (bad cholesterol) increase risk of Alzheimer's disease (AD)?

Study design:
This review article included 26 case-control studies involving 7,033 participants (2,266 Alzheimer's disease patients and 4,767 non-dementia controls).

There was no significant evidence of publication bias according to the results of Egger's test [p = 0.084].

Results and conclusions:
The investigators found results from the meta-analysis of 26 studies revealed higher levels of LDL cholesterol (>121 mg/dL) in Alzheimer's disease than that of non-dementia controls [SMD = 0.35, 95% CI = 0.12 to 0.58, p 0.01], which was consistent with the results of the fixed-effect model [SMD = 0.16, 95% CI = 0.10 to 0.22, p 0.01].
Sensitivity analyses showed that no single study exerted substantial influence on the pooled effect size after sequentially omitting a study.

The investigators found subgroup analysis of age showed LDL cholesterol levels in Alzheimer's disease patients aged 60-70 were higher than that of non-dementia [60 ≤ age 70: SMD = 0.80, 95% CI = 0.23 to 1.37, p 0.01].  

The investigators concluded that elevated concentration of LDL cholesterol (>121 mg/dL) is a risk factor for Alzheimer's disease. This strong association is significant in patients with Alzheimer's disease aged 60-70 years, but vanishes with increasing age. This review article provides a promising strategy for reducing the risk of Alzheimer's disease in patients with hyperlipidemia, which may be achieved by regulating LDL cholesterol concentration between 103.9 and 121 mg/dL with statins. Prospective studies that exclude potential confounders, more scientific design and adequate long-term follow-up are needed to validate this hypothesis.

Original title:
Low-Density Lipoprotein Cholesterol and Alzheimer's Disease: A Systematic Review and Meta-Analysis by Zhou Z, Liang Y, […], Zhao M.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002548/

Additional information of El Mondo:
Find more information/studies on cholesterol and Alzheimer's disease right here.
 

Objectives:
Several epidemiological studies have been performed to evaluate the association of dietary intake of vitamin C-oriented foods (DIVCF) with risk of fracture and bone mineral density (BMD) loss, but the results remain controversial. Therefore, this review article has been conducted.

Does dietary intake of vitamin C-oriented foods decrease risk of fracture and bone mineral density loss?

Study design:
This review article included 4 cohort studies, 11 case-control studies and 2 cross-sectional studies with a total of 19,484 subjects.

The studies received a quality score of ≥5, indicating that the methodological quality of the studies was generally good.

No evidence of publication bias was found in the evaluation of dietary intake of vitamin C-oriented foods and the risk of hip fracture.

Results and conclusions:
The investigators found that the people with a higher dietary intake of vitamin C-oriented foods had a significantly 34% [RR = 0.66, 95% CI = 0.47 to 0.94, I2 = 79.5%, p = 0.000] lower risk of hip fracture.

The investigators found that the people with a higher dietary intake of vitamin C-oriented foods had a significantly 42% [RR = 0.58, 95% CI = 0.38 to 0.89] lower risk of hip fracture in case-control studies.
However, this reduced risk was not significant in cohort studies [RR = 0.92, 95% CI = 0.59 to 1.44]. 

The investigators found that the people with a higher dietary intake of vitamin C-oriented foods had a significantly 34% [RR = 0.66, 95% CI = 0.48 to 0.92] lower risk of osteoporosis.

The investigators found higher dietary intake of vitamin C-oriented foods was negatively associated with the risk of bone mineral density loss at the lumbar spine [pooled r = 0.15, 95% CI = 0.09 to 0.23] and at the femoral neck [pooled r = 0.20, 95% CI = 0.11 to 0.34].

The investigators concluded that higher dietary intake of vitamin C-oriented foods reduces the risk of hip fracture, osteoporosis and bone mineral density loss, suggesting that people should consume more vitamin C to decrease the risk of hip fracture, osteoporosis and bone mineral density loss, particularly lumbar spine and femoral neck.

Original title:
Can Dietary Intake of Vitamin C-Oriented Foods Reduce the Risk of Osteoporosis, Fracture, and BMD Loss? Systematic Review With Meta-Analyses of Recent Studies by Zeng LF, Luo MH, […], Liu J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7008177/

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

Objectives:
Current evidence on associations between intakes of linoleic acid (LA), the predominant n-6 (ω-6) fatty acid and mortality is inconsistent and has not been summarized by a systematic review and meta-analysis. Therefore, this review article has been conducted.

Does higher linoleic acid intake, assessed by dietary surveys or biomarkers decrease mortality from all causes, cardiovascular disease (CVD) and cancer?

Study design:
This review article included 44 prospective cohort studies with 811,069 participants with dietary intake assessment (170,076 all-cause, 50,786 cardiovascular disease and 59,684 cancer deaths) and 65,411 participants with biomarker measurements (9,758 all-cause, 6,492 cardiovascular disease and 1,719 cancer deaths).

Meta-regressions suggested baseline age and dietary assessment methods as potential sources of heterogeneity for the association between linoleic acid and total mortality.

Results and conclusions:
The investigators found when compared with the lowest categories of dietary linoleic acid intake, that the highest categories of dietary linoleic acid intake significantly reduced total mortality risk with 13% [pooled RR = 0.87, 95% CI = 0.81 to 0.94, I2 = 67.9%].

The investigators found when compared with the lowest categories of dietary linoleic acid intake, that the highest categories of dietary linoleic acid intake significantly reduced cardiovascular disease mortality risk with 13% [pooled RR = 0.87, 95% CI = 0.82 to 0.92, I2 = 3.7%].

The investigators found when compared with the lowest categories of dietary linoleic acid intake, that the highest categories of dietary linoleic acid intake significantly reduced cancer mortality risk with 11% [pooled RR = 0.89, 95% CI = 0.85 to 0.93, I2 = 0%].

The investigators found for each standard deviation increment in linoleic acid concentrations in adipose tissue/blood compartments a significantly reduced total mortality risk of 9% [pooled RR = 0.91, 95% CI = 0.87 to 0.95, I2 = 64.1%].

The investigators found for each standard deviation increment in linoleic acid concentrations in adipose tissue/blood compartments a significantly reduced cardiovascular disease mortality risk of 11% [pooled RR = 0.89, 95% CI = 0.85 to 0.94, I2 = 28.9%].

The investigators found for each standard deviation increment in linoleic acid concentrations in adipose tissue/blood compartments a significantly reduced cancer mortality risk of 9% [pooled RR = 0.91, 95% CI = 0.84 to 0.98, I2 = 26.3%].

The investigators concluded higher linoleic acid intake, assessed by dietary surveys or biomarkers, reduces risk of mortality from all causes, cardiovascular disease and cancer. These data support the potential long-term benefits of PUFA intake in lowering the risk of cardiovascular disease and premature death.

Original title:
Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies by Li J, Guasch-Ferré M, […], Hu FB.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32020162

Additional information of El Mondo:
Find more information/studies on linoleic acid intake and mortality right here.
Linoleic acid is a PUFA.
 

Objectives:
Alzheimer's disease (AD) is a common type of dementia, which has caused heavy global economic and health burden and the using of statins to treat Alzheimer disease has caused widely debated. Therefore, this review article has been conducted.

Does statin use decrease Alzheimer disease?

Study design:
This review article included a total of 9 RCTs containing 1,489 patients. Of them, 742 patients in the statins group, 747 patients in the control group (group without statins).

There were 9 studies used the MMSE scale, 5 studies used the ADAS-Cog scale, 4 studies used the NPI scale and 6 studies used the ADL scale.

Sensitivity analysis and publication bias test were both negative and the results were relatively reliable and stable.

Results and conclusions:
The investigators found meta-analysis of the 9 studies that reported the MMSE scale scores indicated that there was no significant effect of statins as compared with control group [pooled WMD = 1.09, 95% CI = -0.00 to 2.18, p = 0.05, I2 = 87.9%].

The investigators found meta-analysis of the 5 studies that reported the ADAS-Cog scale scores also indicated that there was no significant effect of statins as compared with control group [pooled WMD = -0.16, 95% CI = -2.67 to 2.36, p = 0.90, I2 = 80.1%].

The investigators found meta-analysis of the 4 studies that reported the NPI scale scores indicated that treatment with statins significantly slowed the rise in the NPI scale scores as compared with control group [pooled WMD = -1.16, 95% CI = -1.88 to -0.44, p = 0.002, I2 = 45.4%].

The investigators found meta-analysis of the 6 studies that reported the ADL scale scores indicated that treatment with statins significantly improve patients' daily living ability [pooled WMD = -4.06, 95% CI = -6.88 to -1.24, p = 0.005, I2 = 86.7%].

The investigators found results of subgroup analysis indicated that the use of statins in the short term (≤ 12 months) associated with the change of the MMSE scale scores [pooled WMD = 1.78, 95% CI = 0.53 to 3.04, p = 0.005, I2 = 79.6%].

The investigators concluded statins used in Alzheimer disease patients have beneficial effects on the scores of MMSE scale in the short term (≤ 12 months) and statins slow the deterioration of neuropsychiatric status and improve activities of daily living ability in Alzheimer disease patients.

Original title:
The efficacy of statins in the treatment of Alzheimer's disease: a meta-analysis of randomized controlled trial by Xuan K, Zhao T, […], Sun Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31930449

Additional information of El Mondo:
Find more information/studies on dementia right here.
 

Objectives:
Despite growing evidence for the association between other dietary macronutrients and bone health, limited and inconsistent knowledge is available regarding carbohydrate intake. Therefore, this review article has been conducted.

Does a high carbohydrate intake increase risk of fracture?

Study design:
This review article included observational studies.

Results and conclusions:
The investigators found no association between carbohydrate intake and the risk of fracture in high versus low intake meta-analysis [overall relative risk = 1.24, 95% CI = 0.84 to 1.84, p = 0.27, I2 = 57.7%, p = 0.05].

The investigators found, moreover, there was no relationship between carbohydrate intake and the risk of fracture in both linear [overall RR = 1.00, 95% CI = 0.94 to 1.05, p = 0.88, I2 = 68.1%, p = 0.48] and nonlinear [p non-linearity = 0.14] models.

The investigators concluded high carbohydrate intake does not increase risk of fracture.

Original title:
Dietary carbohydrate intake and risk of bone fracture: a systematic review and meta-analysis of observational studies by Mozaffari H, Daneshzad E and Azadbakht L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31982636

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

Objectives:
Which factors increase risk of dementia?

Study design:
This review article included 34 prospective cohort studies, among which 24 were eligible for meta-analysis. A total of 159,594 non-demented adults were enrolled at baseline before 65 years and 13,540 people were diagnosed with dementia after follow-up.

Results and conclusions:
The investigators found obesity significantly increased risk of dementia with 78% [RR = 1.78, 95% CI = 1.31-2.41].

The investigators found diabetes mellitus significantly increased risk of dementia with 69% [RR = 1.69, 95% CI = 1.38-2.07].

The investigators found current smoking significantly increased risk of dementia with 61% [RR = 1.61, 95% CI = 1.32-1.95].

The investigators found hypercholesterolemia significantly increased risk of dementia with 57% [RR = 1.57, 95% CI = 1.19-2.07].
However, the sensitivity analyses showed that the result of hypercholesterolemia was not reliable, which need to be confirmed by more high-quality studies.

The investigators found hypertension significantly increased risk of dementia with 41% [RR = 1.41, 95% CI = 1.23-1.62] for borderline blood pressure.

The investigators found hypertension significantly increased risk of dementia with 72% [RR = 1.72, 95% CI = 1.25-2.37] for high systolic blood pressure.
However, the sensitivity analyses showed that the result of high systolic blood pressure was not reliable, which need to be confirmed by more high-quality studies.

The investigators found hyperhomocysteinemia, psychological stress and heavy drinking were also associated with elevated dementia risk.

The investigators found, in addition, physical exercise, a healthy diet and hormone therapy in middle age were associated with the reduction of dementia risk.

The investigators concluded middle-aged people with obesity or diabetes and current smokers in midlife are at higher risk of developing dementia later in life.

Original title:
Midlife Modifiable Risk Factors for Dementia: A Systematic Review and Meta-analysis of 34 Prospective Cohort Studies by Li XY, Zhang M, [...], Tan L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31902364

Additional information of El Mondo:
Find more information/studies on obesity, diabetes, hypertension and dementia right here.
 

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

Additional information of El Mondo:
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.