Hostility and trajectories of body mass index over 19 years: the Whitehall II Study

The authors examined the associations of hostility measured in adulthood with subsequent body mass index (BMI; weight (kg)/height (m)(2)) assessed at 4 time points over a 19-year period (1985-2004) in a United Kingdom cohort study. A total of 6,484 participants (4,494 men and 1,990 women) aged 35-55 years at baseline (1985-1988) completed the Cook-Medley Hostility Scale. BMI was assessed upon medical examination in phases 1 (1985-1988), 3 (1991-1993), 5 (1997-1999), and 7 (2002-2004). Mixed-models analyses of repeated measures showed clear evidence of increasing BMI over follow-up in both sexes. In women, higher levels of hostility were associated with higher BMI at baseline, and this effect remained constant throughout the follow-up period. In men, hostility levels were also strongly associated with BMI at baseline, but results for the interaction between time and hostility also suggested that this association increased over time, with persons in the highest quartile of hostility gaining an excess of 0.016 units (P = 0.023) annually over the follow-up period as compared with persons in the lowest quartile. The authors conclude that the difference in BMI as a function of hostility levels in men is not stable over time.