Objectives:
Environmental risk factors regrading rheumatoid arthritis (RA) have not been explored extensively. Selenium (Se), zinc (Zn) and copper (Cu) nutrients were reported to associate with rheumatoid arthritis, but the results were inconsistent. Therefore, this review article has been conducted.

Is there a relationship between serum selenium, zinc and copper levels and rheumatoid arthritis risk?

Study design:
This review article included 41 studies.

Objectives:
Vaccinating infants with a first dose of measles-containing vaccine (MCV1) before 9 months of age in high-risk settings has the potential to reduce measles-related morbidity and mortality. However, there is concern that early vaccination might blunt the immune response to subsequent measles vaccine doses. Therefore, this review article (meta-analysis) has been conducted. 

Objectives:
Maternal folic acid supplementation is considered mandatory in almost every country in the world to prevent congenital malformations. However, little is known about the association of maternal folic acid intake with the occurrence of childhood cancer. Therefore, this review article has been conducted.

Does maternal folic acid supplementation during pregnancy reduce risk of childhood cancer?

Scientific studies (review articles) on polio:
One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:

Objectives:
Measles is an important cause of death in children, despite the availability of safe and cost-saving measles-containing vaccines (MCVs). The first MCV dose (MCV1) is recommended at 9 months of age in countries with ongoing measles transmission and at 12 months in countries with low risk of measles.

The aim of this review article is to assess the benefits and risks of MCV1 in infants younger than 9 months.

Study design:

Objectives:
The lipid distribution in people who are overweight and obese is directly related to metabolic diseases. Quercetin supplementation may be an appropriate approach for reducing the risk factors of metabolic diseases in people who are obese. Therefore, this review article has been conducted.

Objectives:
Does green coffee bean extract (GCBE) supplementation reduce blood pressure?

Study design:
This review article included 9 RCTs.

Results and conclusions:
The investigators found a significant reduction in systolic blood pressure (SBP) [WMD = -3.093 mmHg, 95% CI = -3.914 to -2.273, I2 = 0.0%] and diastolic blood pressure (DBP) [WMD = -2.170 mmHg, 95% CI = -2.749 to -1.590, I2 = 46.5%] after green coffee supplementation with low heterogeneity among the studies.

Objectives:
Malaria causes a reduction in haemoglobin that is compounded by primaquine, particularly in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency.

The aim of this review article is to determine the relative contributions to red cell loss of malaria and primaquine in patients with uncomplicated Plasmodium vivax.

Objectives:
Findings of epidemiological studies regarding the association between carrot consumption and lung cancer risk remain inconsistent. Therefore, this review article has been conducted.

Objectives:
The results of epidemiological studies on the relationship between fruit and vegetable intake and lung cancer risk were inconsistent among participants with different smoking status. Therefore, this review article has been conducted.