The impact of climate on the prevalence of respiratory tract infections inearly childhood in Lahore, Pakistan

Background Respiratory tract infections are a major health problem in devel oping countries. The aim of this study was to analyse the impact of the cli mate on the prevalence of upper respiratory tract infection (URTI) and lowe r respiratory tract infection (LRTI) in four socioeconomically different gr oups in a developing country. Methods A prospective cohort study was conducted among children in four soc ioeconomically different groups in Lahore, Pakistan. Monthly observations w ere made on 1476 infants born during 1984-1987 and followed for 24 months. Prevalence of URTI and LRTI was analysed according to age, area of living, family size, time of birth, the season of the year and climate variables su ch as rain, temperature and humidity. Results Low monthly average minimum day temperature was associated with hig h prevalence of URTI and LRTI. For LRTI the impact of temperature was large r for boys, children living in larger families and children living in the p oorer areas. This pattern was not seen for URTI. A peak in prevalence for L RTI was shown at 5-6 months of age for LRTI and at 10-12 months of age for URTI. Conclusions Temperature is related to prevalence of URTI and LRTI in a deve loping society. The effect of temperature on health varies between differen t subgroups. These effects should be considered in planning health actions to prevent respiratory tract infections.