Objectives:
Does vitamin K reduce risk of cardiovascular disease (CVD) events and mortality?

Study design:
This review article included 21 articles with 222,592 participants.

Results and conclusions:
The investigators found dietary phylloquinone (vitamin K1) intake significantly reduced risk of total cardiovascular disease with 8% [pooled HR = 0.92, 95% CI = 0.84 to 0.99, I2 = 0%, 4 studies].
Significant means that there is an association with a 95% confidence.

Objectives:
The role of zinc in the etiology of type 2 diabetes has been widely reported in recent decades. However, much remains uncertain concerning the effect of zinc on the risk of developing type 2 diabetes. Therefore, this review article has been conducted.

Objectives:
Free fatty acids, also known as nonesterified fatty acids, are proinflammatory molecules that induce insulin resistance in nonpregnant individuals. Nevertheless, the concentration of these molecules has not been systematically addressed in pregnant women. Therefore, this review article has been conducted.

Do higher plasma levels of free fatty acids increase risk of gestational diabetes mellitus?

Objectives:
Undernutrition is associated with an elevated risk of mortality among children in low- and middle-income countries. Small-quantity lipid-based nutrient supplements (LNS) have been evaluated as a method to prevent undernutrition and improve infant development, but the effects on mortality are unknown. Therefore, this review article has been conducted.

Do lipid-based nutrient supplements (LNS) reduce all-cause mortality among children 6-24 months old?

Study design:

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.

Objectives:
The relationship between serum copper (Cu) level and overweight/obesity remains controversial. Therefore, this review article (meta-analysis) has been conducted.

Does a high serum copper level increase overweight/obesity risk?

Study design:
This review article included 21 articles.

Results and conclusions:

Objectives:
Current efforts for the prevention of malaria have resulted in notable reductions in the global malaria burden. However, they are not enough. Good hygiene is universally considered one of the most efficacious and straightforward measures to prevent disease transmission. Therefore, this review article has been conducted.

Objectives:
The morbidity of eczema has increased in the recent years and the methods to prevent or ameliorate its effects are becoming more important. Therefore, this review article has been conducted.

Do vitamin supplements reduce risk of eczema?

Objectives:
Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. Therefore, this review article has been conducted.

Do carotenoids (β-cryptoxanthin, α-carotene, β-carotene and lutein and zeaxanthin) reduce risk of bladder cancer?

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].