Aim: To investigate the association between smoking status and body-mass-index (BMI) categories.
Subject and methods: Data are obtained from 2,340 observations from the Malaysia Non-Communicable Disease Surveillance-1. An ordered probability model for BMI categories with ordinal smoking treatment categories is developed and estimated. Marginal and treatment effects are calculated.
Results: Socio-demographic and health-lifestyle factors play significant roles in body weight categories, conditional upon smoking status. Education levels are inversely correlated with BMI categories amongst non-smokers only. Age and income levels are associated with BMI within non-smokers and compulsive smokers. Gender (female), family history of serious illnesses, individual health conditions (hypercholesterolemic, hypertensive), ethnicity (Malays and Indians) and regional locations (metropolitan) are associated with higher BMI levels, irrespective of smoking status. Additionally, BMI categories and levels are closely associated with smoking habits. As individuals switch from non-smoking to casual smoking, the probability of being overweight or obese increases, with an upsurge of 1.89 BMI units. As the casual smoking habit evolves into compulsive smoking, overweight or obese likelihoods are lowered as individuals are more likely to be in the underweight, normal weight or at-risk weight BMI ranges instead, while experiencing a decline of 1.75 BMI units.
Conclusions: There exists close association between BMI categories and levels with smoking habits. As smoking tendencies develop from being a non-smoker to a casual (compulsive) smoker, overweight or obese likelihoods increase (decrease), as individuals realize an upsurge (reduction) in BMI levels.
Study name: Malaysia Non-Communicable Disease Surveillance-1 (MyNCDS-1) survey