Table 1.

Description of PICOS criteria for a systematic review assessing the effects of micronutrients supplementation or administration on the prevention and management of common cold and pneumonia

Variable	Description
Population	Prevention: healthy individuals aged between 18 and 65 years
	Management: individuals aged between 18 and 65 years, infected with common cold or pneumonia
	Oral administration or supplementation of a singular micronutrient.
Intervention	Micronutrients of interest: minerals (copper, iron, magnesium, selenium, and zinc) and vitamins (vitamins A, B, D, E, and K)
Comparator	Control groups without any micronutrient administration or supplementation
Outcome	Incidence, duration, or severity of common cold (primary outcome) or community-acquired pneumonia (secondary outcome)
Study design	Randomized controlled trials
Research question	Does 1) regular oral supplementation of a micronutrient singly prevent cold incidence or 2) oral provision of a micronutrient singly when infected decreases cold duration or severity among healthy individuals aged between 18 and 65 years?

PICOS = population, intervention, comparator, outcome, study design.