Is leg length a biomarker of childhood conditions in older Chinese women? The Guangzhou Biobank Cohort Study
- C M Schooling1,
- C Q Jiang2,
- M Heys,
- W S Zhang2,
- X Q Lao1,
- P Adab3,
- B J Cowling1,
- G N Thomas1,
- K K Cheng3,
- T H Lam1,
- G M Leung1
- 1Department of Community Medicine, and School of Public Health, The University of Hong Kong, Hong Kong SAR, China
- 2Guangzhou Occupational Diseases Prevention and Treatment Centre, Guangzhou Number 12 Hospital, Guangzhou, China
- 3Department of Public Health and Epidemiology, University of Birmingham, UK
- Professor T H Lam, Department of Community Medicine, and School of Public Health, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong;
- Accepted 20 March 2007
Objective: In developed western populations longer legs have been shown to be a biomarker of better early childhood conditions. It was hypothesised that in transitioning populations better childhood conditions may bring forward puberty and thus decrease leg length, counteracting the overall positive effect of a favourable childhood environment on leg growth.
Design: Structural equation modelling was used to assess the interrelationship of age, education, father’s job, age of menarche and leg length in a cross-sectional sample of 7273 Chinese women aged at least 50 years from the Guangzhou Biobank Cohort Study.
Results: Leg length had no significant association with education or father’s occupation on bivariable testing. After including age of menarche in the model, education was associated with longer legs (0.45 cm longer per 10 years of education, 95% CI 0.20 to 0.71). Education was also associated with younger age of menarche (1.21 years younger per 10 years of education, 95% CI 1.09 to 1.34), which was in turn associated with shorter legs (0.23 cm shorter per year of menarche earlier, 95% CI 0.18 to 0.27).
Conclusions: In older Chinese women leg length is not a universal biomarker of childhood conditions, when proxied by her educational level and father’s occupation. Nutritionally driven epigenetic influences operating over generations may constrain growth in very recently developed populations. Given the impact of childhood conditions on health, and the dearth of long-term records outside the industrialised world, a greater understanding of the influences on growth in the developing world is required.
Funding: The study was funded by the University of Hong Kong Foundation for Development and Research, and the University of Hong Kong University Research Committee Strategic Research Theme Public Health, Hong Kong; Guangzhou Public Health Bureau, and Guangzhou Science and Technology Bureau, Guangzhou, China; and the University of Birmingham, UK. The funding sources had no role in any of the following: study design; collection, analysis, and interpretation of data; the writing of the report; and the decision to submit the paper for publication.
Competing interests: None declared.