Change In Body Mass Index (BMI) Among Chinese In A General Population: The FAMILY Cohort

Abstract

Background: Studies on the short-term natural changes in BMI are mostly based on Western populations. Hong Kong, the most Westernized and urbanized city of China, may function as an epidemiological sentinel on obesity for other rapidly developing regions in China and Asia.

Aims: To describe the 2-year natural changes in individual BMI among Chinese aged 15 years and above in the FAMILY Cohort, a population-based cohort in Hong Kong.

Key methods: Under Hong Kong FAMILY Project, a Jockey Club Initiative for a Harmonious Society, the weight and height of 11,797 randomly selected participants were measured in Wave 1 (2009-11) and 2 years later in Wave 2 (2011-14) of the FAMILY Cohort. BMI status was defined based on the WHO’s cut-off points for Asian populations.

Results: Mean BMI (SD) increased from 23.57 (3.92) to 23.61 (3.88) (p<0.001) over 2 years. The prevalence of overweight/obese (BMI ³ 23) increased from 52.2% to 52.5%. The prevalence increased in both men (56.2% to 57.9%) and women (48.9% to 49.4%), in which the increase among men was not significantly larger than that in women (p=0.31). 14.8% of participants who were normal/underweight in Wave 1 became overweight/obese in Wave 2, whereas 11.4% of those who were overweight/obese became normal/underweight.

Conclusions: Our findings from a large, population-based cohort describe the short-term natural changes in BMI among Chinese. Future studies examining baseline factors predicting such changes are needed.