Objectives:
Does smoking increase risk for COVID-19 mortality?

Study design:
This review article included 73 articles with 863,313 COVID-19 patients.

Results and conclusions:   
The investigators found that smoking was significantly associated with an increased risk of 19% for death in patients with COVID-19 [pooled relative risk = 1.19, 95% CI = 1.12 to 1.27]. Sensitivity analysis indicated that these results were stable and robust.

Objectives:
Magnesium supplementation is often purported to improve sleep; however, as both an over-the-counter sleep aid and a complementary and alternative medicine, there is limited evidence to support this assertion. Therefore, this review article (meta-analysis) has been conducted.

Objectives:

Objectives:
Do high maternal or neonatal DHA and/or EPA levels increase offspring birth weight and weight in childhood?

Study design:
This review article included 27 RCTs with 6,408 infants and 14 observational studies.

Results and conclusions:
The investigators found in RCTs that >650 mg/day DHA and/or EPA supplementation significantly increased birth weight [MD = 87.5g, 95% CI = 52.3 to 122.6, n = 3,831 participants, moderate quality].

Objectives:
Have enteral zinc supplementation positive effects on growth and neurodevelopmental outcomes of preterm infants?

Study design:
This review article included 8 RCTs with 742 infants.
7 studies reported growth anthropometrics at 3-6 months corrected age (CA) and 2 studies reported neurodevelopmental outcomes at 6-12 months CA.

Evidence was "moderate" certainty for weight and length and "very low" certainty for neurodevelopment.

Objectives:
The associations of alcohol consumption and venous thromboembolism (VTE) have been investigated widely, but the conclusions were inconsistent. Therefore, this review article has been conducted.

Objectives:
Does mushroom dietary intake reduce risk of cancer at any site?

Study design:
This review article included 11 case-control studies and 6 cohort studies.

Results and conclusions:
The investigators found higher mushroom consumption significantly reduced total cancer with 34% [pooled RR for the highest compared with the lowest consumption groups = 0.66, 95% CI = 0.55 to 0.78, n = 17].

Objectives:
What are the efficacy and side effects of COVID-19 vaccines?

Study design:
This review article included 25 randomized studies (123 datasets) with 58,889 cases that received the COVID-19 vaccine and 46,638 controls who received placebo.
Out of 58,889 vaccine cases, 31,070 were male and 27,819 female.
Out of 46,638 individuals in the placebo group, 33,354 were male and 13,284 female.
Out of 25 randomized studies, 12 were double-blind, 2 participant-blind, 6 observer-blind, 3 single-blind and 2 partially blind.

Objectives:
Does coffee or tea consumption reduce the risk of glioma?

Study design:
This review article included 12 unique studies (cohort and case-control studies) comprising of 1,960,731 participants with 2,987 glioma cases.

Results and conclusions:
The investigators found in pooled analyses that higher tea consumption was significantly associated with a lower risk of 16% for glioma [RR = 0.84, 95% CI = 0.71 to 0.98, p = 0.030, I2 = 16.42%].

Objectives:
A few randomized controlled trials (RCTs) have assessed the effect of brown rice consumption on metabolic parameters (such as, weight, height, waist circumference, fasting glucose, LDL, HDL, total cholesterol, triglycerides and blood pressure) compared to white rice, with inconsistent findings. Therefore, this review article has been conducted.