Association between secondhand smoke exposure at home and cognitive performance among rural primary school children in Malaysia

INTRODUCTION: Secondhand smoke (SHS) exposure is linked to a series of serious health problems. Children may be particularly vulnerable to the effects of SHS exposure at home. This study aimed to determine the association between SHS exposure at home and cognitive performance in school children.

METHODS: A multistage sampling was performed across rural primary schools in Kuala Krai, Kelantan, Malaysia. Data were collected using self-administered questionnaires and the children aged 10-11 years (n=312) were subjected to cognitive tests including digit span, letter-number sequencing, coding, and symbol search. Cognitive performance was tested using subscales derived from the Wechsler Intelligence Scale for Children.

RESULTS: The prevalence of SHS exposure at home was 55.8%, where 11.9% of children lived with one smoker, while 43.9% of children lived with ≥2 smokers. There was a significant difference in the mean score of the combined cognitive tests between SHS-exposed and non-exposed children after adjustment for sex, parental educational level, family income and academic performance [Pillai's Trace=0.084, F statistic (df)=6.803 (4302), p<0.001].

CONCLUSIONS: More than half of the primary school children in rural Kuala Krai were exposed to SHS from at least one smoker at home. There was a significant association between SHS exposure at home and cognitive performance.