Objectives:
Evidence has shown that essential nutrients are highly correlated with the occurrence of esophageal cancer (EC). However, findings from observational studies on the associations between dietary carbohydrate, salt consumption and the risk of esophageal cancer remain controversial. Therefore, this review article has been conducted.

Objectives:
Despite growing evidence for the association between other dietary macronutrients and bone health, limited and inconsistent knowledge is available regarding carbohydrate intake. Therefore, this review article has been conducted.

Does a high carbohydrate intake increase risk of fracture?

Study design:
This review article included observational studies.

Objectives:
Micronutrient deficiencies continue to be widespread among children under-five in low- and middle-income countries (LMICs), despite the fact that several effective strategies now exist to prevent them. This kind of malnutrition can have several immediate and long-term consequences, including stunted growth, a higher risk of acquiring infections and poor development outcomes, all of which may lead to a child not achieving his or her full potential.

Objectives:
Which factors are associated with the risk of stomach cancer?

Study design:
This review article included 232 observational studies involving 33,831,063 participants.

Results and conclusions:
The investigators found H. pylori infection significantly increased risk of stomach cancer with 156% [OR = 2.56, 95% CI = 2.18 to 3.00].

The investigators found formerly smoked significantly increased risk of stomach cancer with 43% [OR = 1.43, 95% CI = 1.29 to 1.59].

Objectives:
Alzheimer's disease (AD) is a common type of dementia, which has caused heavy global economic and health burden and the using of statins to treat Alzheimer disease has caused widely debated. Therefore, this review article has been conducted.

Does statin use decrease Alzheimer disease?

Study design:
This review article included a total of 9 RCTs containing 1,489 patients. Of them, 742 patients in the statins group, 747 patients in the control group (group without statins).

Objectives:
Adolescents and young adults are at a high risk of developing human papillomavirus (HPV) infections, which can be prevented with the use of vaccines. Moreover, a combined immunization strategy for administration of HPV vaccines with other routine vaccines may lead to better compliance.

Objectives:
The activity of hepatitis B virus (HBV) as a risk factor for the incidence and progression of chronic kidney disease (CKD) has not been clarified. Therefore, this review article has been conducted.

Does hepatitis B virus infection increase risk of chronic kidney disease?

Objectives:
Epidemiologic studies have investigated the association between nut intake and risk for multiple cancers. However, current findings are inconsistent and no definite conclusion has been drawn from prospective studies. Therefore, this review article has been conducted.

Does nut consumption reduce cancer risk?

Study design:
This review article included 33 cohort studies with more than 50,000 cancer cases.

Objectives:
The benefits of LDL cholesterol-lowering treatment for the prevention of atherosclerotic cardiovascular disease are well established. However, the extent to which these effects differ by baseline LDL cholesterol, atherosclerotic cardiovascular disease risk and the presence of comorbidities remains uncertain. Therefore, this review article has been conducted.

Objectives:
The goal of this review article is to determine the effectiveness of micronutrients in the cure and treatment of pulmonary tuberculosis.

Study design:
This review article included a total of 16 RCTs (receiving oral micronutrients for at least 4 weeks compared with placebo) with 4,398 people.

Results and conclusions:
The investigators found zinc supplementation did not significantly reduced mortality [MD = 0.04, 95% CI = 0.00 to 0.08] in patients with pulmonary tuberculosis.