Table 1.

PICOS criteria for inclusion and exclusion of studies

Parameter	Inclusion/exclusion criteria	Data extraction
Patient	Infertile men (men with the following disorders: sperm dysfunction, sperm DNA damage, varicocele, or idiopathic oligozoospermia)	Location, age, patient groups (trials only), type of infertility
Intervention	Oral administration of micronutrients (reports in which this was given in addition to other compounds were also eligible), assessment of food intake or dietary pattern	Type of micronutrient or assessment, dosage, duration of follow-up, any additional compound given
Comparators	Placebo, no micronutrient intake, different diets or food intakes	Numbers in the intervention and comparator groups, when relevant (trials only)
Outcome	Pregnancy rate, semen parameters, and semen quality (sperm concentration, motility, and morphology)	Details of sperm parameters, method of identification, treatment, and outcome. Effect of the intervention on clinical endpoints
Study design	Experimental studies (randomized trials), longitudinal studies (prospective and retrospective cohorts), case–control studies, and cross-sectional studies	Type of study design, and numbers in the intervention and comparator groups (trials only)