Secular trends since the 1970s and racial/ethnic and SES disparities in linear (height) growth in US children and adolescents

With NHANES data (1971–74, 1988–94, 2003–08), we examined ethnic, SES disparities in secular trend of height growth. The trend continued, but slowed down since 1988–94, and varied across ethnic‐, SES groups. During 1988–2008, average 10‐y‐increment was ~0.5 cm, except for 10–17‐y Mexican American (MAm) boys (~2 cm). In 2003–08, stunting prevalence (height < 85%tile of CDC 2000 Growth Charts) was about 10% in whites and backs, but higher in MAm (16% boys,19% girls). From 1988–1994 to 2003–08, stunting % in MAm decreased by 2 percentage points in boys and 1 in girls per decade. It did not decrease much in whites and blacks in this period, but by ~2 percentage points (per decade) between 1971–74 and 1988–1994. In all NHANES waves, height was positively associated with family income (ie, poverty income ratio, PIR; scales 0 to 5‐high income), but with a reduction in the association and variation across ethnicity. In 2003–08, controlling for age, sex, ethnicity, (1) one unit increase in PIR associated with an increase by ~0.5 cm and a 10% reduction (relative) in stunting rate ( P < 0.001); (2) compared with the highest income group (PIR ≥4), the lowest income (PIR < 1) were ~2 cm shorter and 52% more likely (relative) to be stunted ( P < 0.001). Income effect was most pronounced in 10–19‐y MAm. In recent decade overall height growth appeared to level off in US children, but it remained substantial in some minority and low‐income groups.