Slow-growing infants may become hostile adults

NEW YORK (Reuters Health) - Adults with higher levels of hostility are more likely to be lighter at birth and throughout childhood than less hostile people according to a study published in journal Psychosomatic Medicine.

Hostility has been linked to risk of cardiovascular disease and all-cause mortality, but it is uncertain why this occurs, note Dr. Katri Raikkonen, of the University of Helsinki, Finland, and colleagues. They suggest that a common underlying origin may be low fetal and early postnatal development.

The researchers studied 939 women and 740 men born in Helsinki between 1934 and 1944 who completed a test called the Cook-Medley Hostility Scale at an average age of 63.4 years. The authors then estimated the subjects' growth patterns from birth, child welfare, and school records. Adult body size was also measured in a physical examination.

Study participants with higher levels of hostility had a lower body weight and smaller body mass index at birth - they also had a slower than average weight gain from birth to 6 months of age and throughout childhood. These subjects, however, became heavier in adulthood, the investigators report.

Individuals with higher levels of hostility also tended to be shorter in the first year of life and were also shorter in adulthood. The authors note that this growth trajectory was mostly attributable to slower growth in stature from birth to 6 months compared with any other factors.

"These two trajectories of growth that characterized men and women with higher levels of hostility are to a large extent comparable to the trajectories that our study group has shown to depict men and women who have coronary events, stroke, or type 2 diabetes as adults," Raikkonen and colleagues point out.

The effects appeared to be unrelated to sex, father's occupational status, mother's age at delivery, number of siblings, breastfeeding or education level attained by adulthood, they note.

"Against this background," the researchers conclude, "we interpret our findings as suggesting that hostility and cardiovascular disease may share a common vulnerability factor in fetal and early postnatal life."

Psychosomatic Medicine, April 2008.