The impact of season and climate on growth during early childhood in different socio-economic groups in Lahore, Pakistan

Abstract

Aim. The aim of this study was to analyse the impact of season and climate on early child growth in four socio-economically different groups living in Lahore, Pakistan. Methods. A prospective cohort study was conducted among children living in a village, periurban slum area, urban slum area and a group of children from the upper middle class. Monthly observations were made on 1476 infants from birth to 24 months. Growth in terms of length and weight were analysed in relation to age, socioeconomical group, and season of the year and different climate variables such as rain, day temperature and humidity. The longitudinal data was analysed by the derived variable method and regression models.

Results. Season of birth did not have any important impact on the birth weight or length. There were differences in weight gain during the first six months as well as between 6-12 months, depending on which time of the year the child was born. This seasonal differences was most prominent in the poorer groups. The climate variable mean day temperature was negatively correlated to weight gain with a p-value<0001 for the regression coefficient in all groups except for the upper middle class. In the poorer groups the impact increased with age up to 14 months and decrease with higher ages. Growth velocity concerning length was not clearly related to season and climate. In the upper middle class neither season nor climate markedly affected weight or length velocity.

Conclusions. Season and climate are modifying growth. The socio-economic level and the age of the child influence the impact of climate on growth. Together with age, sex and length of gestation, season is an important factor when comparing growth of children living in poor environments.