Vitamin-D status is not a confounder of the relationship between zinc and diarrhoea: a study in 6-24-month-old underweight and normal-weight children of urban Bangladesh

• Published in: European journal of clinical nutrition Vol. 70; no. 5; pp. 620 - 628
• Main Authors: Ahmed, A M S, Magalhaes, R J S, Ahmed, T, Long, K Z, Hossain, MdI, Islam, M M, Mahfuz, M, Gaffar, S M A, Sharmeen, A, Haque, R, Guerrant, R L, Petri, Jr, W A, Mamun, A A
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 01.05.2016
• Subjects: Alfacalcidol; Babies; Bangladesh - epidemiology; Calcifediol; Child, Preschool; Children; Comparative analysis; Diagnosis; Diarrhea; Diarrhea - blood; Diarrhea - epidemiology; Diarrhea - etiology; Diarrhea in children; Female; Health aspects; Humans; Ideal Body Weight - physiology; Immunomodulation; Incidence; Infant; Male; Micronutrients; Morbidity; Multivariate Analysis; Nutrition; Patient outcomes; Poisson Distribution; Preschool children; Product/Service Evaluations; Risk factors; Severity of Illness Index; Thinness - blood; Thinness - complications; Underweight; Urban Population; Vitamin D; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - etiology; Zinc; Zinc - blood; Zinc - deficiency; Zinc in the body; Bangladesh
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/ejcn.2016.7

The role of micronutrients particularly zinc in childhood diarrhoea is well established. Immunomodulatory functions of vitamin-D in diarrhoea and its role in the effect of other micronutrients are not well understood. This study aimed to investigate whether vitamin-D directly associated or confounded the association between other micronutrient status and diarrhoeal incidence and severity in 6-24-month underweight and normal-weight children in urban Bangladesh. Multivariable generalised estimating equations were used to estimate incidence rate ratios for incidence (Poisson) and severity (binomial) of diarrhoea on cohorts of 446 normal-weight and 466 underweight children. Outcomes of interest included incidence and severity of diarrhoea, measured daily during a follow-up period of 5 months. The exposure of interest was vitamin-D status at enrolment. Normal-weight and underweight children contributed 62 117 and 62 967 day observation, with 14.2 and 12.8 days/child/year of diarrhoea, respectively. None of the models showed significant associations of vitamin-D status with diarrhoeal morbidity. In the final model, zinc-insufficient normal-weight children had 1.3 times more days of diarrhoea than sufficient children (P<0.05). Again zinc insufficiency and mother's education (1-5 and >5 years) had 1.8 and 2.3 times more risk of severe diarrhoea. In underweight children, older age and female had 24-63 and 17% fewer days of diarrhoea and 52-54 and 31% fewer chances of severe diarrhoea. Vitamin-D status was not associated with incidence and severity of diarrhoea in study children. Role of zinc in diarrhoea was only evident in normal-weight children. Our findings demonstrate that vitamin-D is not a confounder of the relationship between zinc and diarrhoea.