Ethnic differences in anthropometry among adult Singaporean Chinese, Malays and Indians, and their effects on lung volumes

When standing height (StndHt) cannot be assessed, arm span (AS) or sitting height (SitHt) has been used as surrogate variables for prediction of StndHt in adult caucasians and blacks. We examined (1) the relationship between StndHt, AS and SitHt among adult Chinese, Malays and Indians; and (2) whether anthropometry could explain the ethnic differences in lung volumes (as StndHt-adjusted lung volumes are known to differ significantly: Chinese > Malays > Indians). We recruited 1250 consecutive outpatients aged 20-90 years. Prediction equations of StndHt (with AS, SitHt, weight, age as predictors) for each subgroup of race and sex were formulated with multiple linear regressions. Equations with both AS and SitHt as predictors had the best goodness of fit (SEE = 2.37-2.85 cm, adjusted R2 = 0.67-0.87), as compared to equations with either AS (SEE = 3.00-3.91 cm, adjusted R2 = 0.58-0.80) or SitHt alone (SEE = 3.48-4.00 cm, adjusted R2 = 0.45-0.76). GLM general factorial analyses found that age- and weight-adjusted SitHt-to-StndHt ratios differed significantly among Chinese (0.539), Malays (0.529) and Indians (0.518). This paralleled the ethnic differences in lung volumes. The equations with both AS and SitHt as predictors provide the most accurate estimate of StndHt. Ethnic differences in upper body segment length may explain in part the lung volume differences.
Study site: Respiratory clinic, Tan Tock Seng Hospital, Singapore