Growing up under generalized violence: an ecological study of homicide rates and secular trends in age at menarche in Colombia, 1940s-1980s.

We examined secular changes in mean age at menarche among 5577 Colombian women born between 1941 and 1989, and correlated those changes with nation-wide rates of homicide and real gross domestic product per capita (GDP) at the year of birth and at the year at age 5, within predefined historical periods. The mean (standard error) rate of change in age at menarche by year of birth was -0.55 (0.02) years/decade. The rate of change was not constant, but varied between historical periods as follows: -1.44, -0.14, -0.60, and -0.36 years/decade for the periods 1941-1947, 1948-1958, 1959-1978, and 1979-1989, respectively. The changes in age at menarche correlated positively with the changes in the nation-wide rates of homicide within such periods; i.e. decelerations in the menarcheal trend coincided with increases in the rates of homicide and vice versa. The correlation was higher with the rates of homicide when women were 5 years of age (r=0.99, p=0.01) compared to the rates of homicide at the year of birth (0.55, p=0.45). There were negative correlations between the changes in age at menarche and the changes in GDP, but they were weaker than those with the rates of homicide. These results could suggest a potential impact on maturation of psychosocial stress in childhood due to exposure to a generalized atmosphere of violence and fear.