Information collection
| Identification of the study | Title, first author’s last name, year of publication, journal, volume, number and pages |
| Study characteristics | Participant recruitment period, country, region, study design, study site, study setting, sampling process, data collection time, sample size. |
| Participant characteristics | Information on study inclusion and exclusion criteria, mean/median age, ethnicity, proportion of participants with any therapy. |
| Diagnosis and classification of the condition | Measurement or diagnostic criteria used to define the condition (micronutrient deficiency), micronutrient evaluated, unit of measurement, cut-off point adopted. |
| Prevalence and incidence | No of participants, total person follow-up time, no of cases of the condition, reported aetiologies, prevalence, incidence rate and their respective CIs and/or p value. |