Height at age 18 years is a strong predictor of attained education later in life: cohort study of over 950 000 Swedish men

Background. Adult body height has been related to socioeconomic position in cross-sectional studies. Intelligence, shared family factors, and non-familial circumstances may contribute to associations between height and attained education, but their relative importance has been difficult to resolve. Methods. A nation-wide record-linkage cohort study of over 950 000 Swedish men born 1950-75 followed with respect to attained education for up to 27 years after measurement of height at age 18 (baseline). The association between height and attained education in later life was investigated by logistic regression modelling with adjustment for age, geography, parental socioeconomic position, and cognitive ability. Shared family factors were accounted for in analyses of full-brother-pairs using conditional logistic regression. Results. The odds ratio (OR) for attaining higher education 7- 27 years after baseline was 1.10 [95% confidence interval (95% CI) 1.09-1.10] in fully adjusted models per 5 cm increase in height. Men taller than 194 cm were two to three times more likely to obtain a higher education as compared with men shorter than 165 cm. The association remained within brother-pairs, OR 1.08 (95% CI 1.07-1.10), suggesting that non-familial factors contribute to the association between height and education attainment. A significant interaction (P < 0.0001) was found between year of birth, height, and attained education, showing slightly weaker associations among later birth cohorts. Conclusions. The strong positive association between height and educational achievement remaining after adjustment for year of birth, parental socioeconomic position, other shared family factors, and cognitive ability may reflect educational discrimination based on height although residual confounding cannot be ruled out.