Objectives:
Are cardiovascular drugs associated with poor COVID-19 outcomes?

Study design:
This review article included 390 studies.

Results and conclusions:   
The investigators found the most-reported drugs were angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin receptor blockers (ARBs) with ACEI/ARB exposure having borderline association with confirmed COVID-19 infection [OR = 1.14, 95% CI = 1.00 to 1.31].

Objectives:
Does carotenoid (like astaxanthin, lutein/zeaxanthin, β-cryptoxanthin and lycopene) supplementation have protective effects on inflammatory biomarkers (like C-reactive protein and interleukin-6)?

Study design:
This review article included 26 RCTs with 35 effect sizes.

Objectives:
Preliminary studies showed that coronavirus disease 2019 (COVID-19) disrupts body immune system, including dysregulation of cytokine interleukin-6 (IL-6). IL-6 inhibitors agents have been used as treatment options for COVID-19, yet their benefit as therapeutic agents remains unclear. Therefore, this review article (meta-analysis) has been conducted.

Objectives:
The evidence on the association between obesity and atrial fibrillation (AF) recurrence was equivocal. Therefore, this review article (meta-analysis) has been conducted.

Objectives:
Do rotavirus vaccines reduce risk of rotavirus gastroenteritis (RVGE) in children younger than 5 years?

Study design:
This review article included 20 RCTs and 38 case-control studies.

Objectives:
Does chromium supplementation improve lipid profile (serum levels of triglyceride and cholesterol) in patients with type 2 diabetes mellitus (T2DM)?

Study design:
This review article included  24 RCTs (with 28 effect sizes).

Results and conclusions:
The investigators found that chromium supplementation resulted in a significant decrease in serum levels of triglyceride (TG) in patients with type 2 diabetes mellitus [MD = -6.54 mg/dL, 95 % CI = -13.08 to -0.00, p = 0.050].

Objectives:
L-carnitine is an amino acid derivative that is thought to be helpful for treating renal anemia in hemodialysis patients. However, the mechanism remains to be fully elucidated. Therefore, this review article (meta-analysis) has been conducted.

Does L-carnitine supplementation/therapy have positive effects on renal anemia in hemodialysis patients?

Study design:
This review article included 18 RCTs with 1,090 participants.

Objectives:
What is the pooled prevalence of COVID-19 in patients with MS?

Study design:
This review article included 12 articles with 101,462 patients and the total number of possible/confirmed cases was 1,394.
Mean age ranged from 35 to 54 years. Totally, 49 patients died.
The quality assessment score ranged between 4 and 10.

Objectives:
Does vitamin B supplementation have positive effects on patients with mouth ulcers?

Study design:
This review article included 16 RCTs with 1,534 patients (767 in the treatment group and 767 in the control group).
Patients who did not receive treatment were taken as controls, while those who were treated with vitamin B alone or vitamin B combined with pantothenic acid were included in the treatment group.

Results and conclusions:

Objectives:
Due to the rapid increase of primary liver cancer incidence and the poor prognosis, it is imperative to identify new modifiable factors such as diet and nutrition for the prevention of liver cancer. Diet high in saturated fatty acids (SFA) has been hypothesized to be associated with increased risk of cancers. However, the associations between dietary fatty acids and liver cancer are not consistent. Therefore, this review article has been conducted.