When the sample was split (roughly in half) by period, the MLDA-associated risk for women was significant both in the 1990–1996 and 1997–2004 periods, though there was a very small tendency toward lower risk in the latter period, suggesting MLDA effects may wane with age. This trend of lower risk in the latter period was more pronounced in the case of homicide (Table 3). When splitting the sample by birth cohort, there was no significant MLDA-associated risk observed for women (or men) born between 1949 and 1959 -- the birth cohorts who came of age during a period of liberalized drinking age laws. In contrast, the odds ratios for the 1960–1972 birth cohort -- who came of age as drinking age laws were being raised in response to public health concerns -- tended to be larger than those observed in the full sample analyses, and significantly higher than those observed for the 1949–1959 birth cohort. Hence, there are two interactions that need to be discussed: the interaction between MLDA and sex, and for women, the interaction between MLDA and birth
