Professor Dr. C. Mary Schooling of the CUNY Graduate School of Public Health and Health Policy along with colleagues from the University of Hong Kong studied ways to clarify social patterning of obesity and differences by sex in Hong Kong. It was published in the PLoS One.
[Photo: Dr. C. Mary Schooling]
In Hong Kong childhood BMI is not clearly socially patterned. The research utilized data from the Children of 1997, a population-representative Chinese birth cohort. The researchers examined the association of low parental education attainment, as a proxy of low socio-economic position, with general and central adiposity in adolescents and any differences by sex.
The main exposure was highest parental education (< Grade 9, Grade 10-11, and > Grade 12) at child’s birth. The main outcome was general adiposity at 14 years. The researchers assessed adiposity from Student Health Service data, or if not available by self-report. Subjects were between 12.0 and 14.9 years at the time of measurement. The researchers calculated central adiposity using waist-to-height ratio.
Parental education of Grade 9 or below, compared to Grade 12 or above, was associated with higher waist-height ratio z-score particularly in girls (0.30, 95% confidence interval (CI) 0.19, 0.41) compared to boys (0.12, 95% CI 0.02, 0.22) (p for sex interaction = 0.02). Lower parental education was associated with greater BMI z-score in adolescents of locally born mothers, but not adolescents of migrant mothers, with no difference by sex.
Different social patterning in different markers of adiposity may imply different sociological and biological mediating pathways. A stronger association between low early life socio-economic position and waist-height ratio in adolescent girls may indicate sex-specific influences of socio-economic position related early life exposures on central adiposity.