Intellectual and Physical Performance and Morbidity in Relation to Height in a Cohort of 18-Year-Old Swedish Conscripts

Abstract

To test whether short stature in young men without malformations or chronic childhood diseases is associated with intellectual and physical performance and morbidity, a large cohort of apparently healthy 18-year-old Swedish men was analysed. The original cohort consisted of all men born in 1976 and conscripted in 1994 (n = 38,900). After exclusion due to growth-affecting disorders or missing data, 32,887 subjects were available for analysis. Short conscripts (height below or equal to –2 SD scores) demonstrated increased overall morbidity compared with taller conscripts (above –2 SD scores). Specifically, short conscripts had more psychiatric and musculoskeletal diagnoses and were more often considered psychologically unsuitable for military service. Mean intellectual performance increased continuously with height; the mean ‘standard nine’ score was 4.22 for the short men and 5.17 for the rest (p < 0.001). Short conscripts scored less well than taller conscripts in assessment of psychological functioning during mental stress, and were evaluated as less suitable for leadership positions. Maximal working capacity per kilogramme body weight correlated negatively with height (p < 0.001). In conclusion, short stature was associated with increased morbidity and psychological problems and with lower mean intellectual performance. To what extent this association is direct or indirect needs further evaluation.