Objectives:
A growing number of epidemiological studies have suggested a possible association between long-chain omega-3 polyunsaturated fatty acid (PUFA) intake and the risk of cancers, but the results have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Objectives:
Testing is one of the commendable measures for curbing the spread of coronavirus disease (COVID-19). But, it should be done using the most appropriate specimen and an accurate diagnostic test such as real time reverse transcription polymerase chain reaction (qRT-PCR). Therefore, this review article has been conducted.

Objectives:
Is coagulation dysfunction associated with severity of COVID-19?

Study design:
This review article included 34 studies involving 6,492 COVID-19 patients.

Results and conclusions:   
The investigators found meta-analysis showed that COVID-19 patients with severe disease had significantly lower platelet count [WMD = -16.29x109 /L, 95% CI = -25.34 to -7.23] and shorter activated partial thromboplastin time [APTT; WMD = -0.81s, 95% CI = -1.94 to 0.33].  

Objectives:
Is there a causal relationship between black or green tea consumption and lowering blood pressure in subjects with elevated blood pressure (BP) or hypertension?
 
Study design:
This review article included 5 RCTs with 408 individuals.

None of the studies reported any side effects.

Objectives:
Are acute kidney injury, acute liver injury and coagulopathy associated with poor composite outcome in patients with COVID-19?

Study design:
This review article included 15 studies with 3,615 COVID-19 patients.
The mean Newcastle-Ottawa scale of the included studies was 7.3 ± 1.2.

Objectives:
Are declined circulating vitamin D levels associated with severity of hepatitis C virus (HCV) infection?

Study design:
This review article included 28 studies, consisting of 7,736 HCV-infected patients and 14,061 control subjects without liver diseases.

Results and conclusions:
The investigators found compared to controls, circulating vitamin D levels were significantly lessened in HCV-infected patients [MD = -14.15, 95% CI = -20.51 to -7.80].

Objectives:
What are the risk factors for the COVID-19-related death?

Study design:
This review article included 15 articles with 2,401 COVID-19 patients.

Results and conclusions:   
The investigators found meta-analysis showed that 66.6% of COVID-19 deceased were male, with a median age of 69.9 years.

The investigators found common symptoms of deceased included fever [70.6 to 100%], dyspnea [38.89 to 85.7%], cough [22.4 to 78% and fatigue [22 to 61.9%].

Objectives:
What is the proportion of health care workers (HCW) who are COVID-19 positive?

Study design:
This review article included 11 studies from December-31, 2019 to April-23, 2020.
The search was limited to the studies that reported the data on the number of COVID-19 positive healthcare workers, among the COVID-19 positive patients.
Case reports, duplicate publications, reviews and family-based studies were excluded.

Results and conclusions:   

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

Objectives:
Has corticosteroid therapy a beneficial role in the management of severely ill COVID-19 patients?

Study design:
This review article included studies with 10,815 ARDS cases among COVID-19 patients.

Results and conclusions:   
The investigators found overall pooled mortality among 10,815 ARDS cases in COVID-19 patients was 39% [95% CI = 23% to 56%].