Cross-sectional studies, which collect information at a single point in time, generally find that young Americans report having more lifetime alcohol problems than older Americans, despite having had less time to develop these problems.

But these studies are hampered by the fact that people of different ages may remember or report problems to different degrees. A new examination of data, collected on similarly aged groups one decade apart, has found substantial increases in drinking and alcohol dependence among women – particularly white and Hispanic women – beginning with those born in the United States after World War II.

“By looking at two different cross-sectional surveys that asked the same questions in the same manner, but were conducted 10 years apart, we were able to compare, for example, 30 - 40 year olds in 2001 with 30 - 40 year olds in 1991,” explained Richard A. Grucza, an epidemiologist at Washington University School of Medicine and the study’s corresponding author. “Essentially, this allowed us to correct for the effects of age on reporting. When we did this, we found that the tendency for young people to have higher levels of lifetime alcohol dependence clearly remained for women, although it disappeared for men.”

Furthermore, added Shelly F. Greenfield, associate clinical director of the Alcohol and Drug Abuse Treatment Program at McLean Hospital, prevalence surveys are inclusive. “Epidemiologic surveys document the prevalence of an illness such as alcohol dependence in the entire population rather than just one segment of the population, such as those seeking treatment,” she said. “This allows us to track trends in illnesses – including whether certain people are more vulnerable for a particular disease, at what age they manifest symptoms, and how quickly the illness progresses.”

For this study, researchers examined two large, national surveys: the National Longitudinal Alcohol Epidemiologic Survey (NLAES), conducted in 1991 and 1992; and the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), conducted in 2001 and 2002. They compared lifetime prevalence rates from the same age groups and demographics, while simultaneously controlling for age-related factors.

“We found that for women born after World War II, there are lower levels of abstaining from alcohol, and higher levels of alcohol dependence, even when looking only at women who drank,” said Grucza. “However, we didn’t see any significant tendency for more recently born men to have lower levels of abstention, or higher levels of alcohol dependence.” He added that these results shed more light on a “closing gender-gap in alcoholism,” showing that it is probably due to higher levels of problems among women, while men have been more or less steady in their levels of dependence.

Greenfield concurred. “This is an excellent study that adds important information to the accumulating evidence that the gender gap between women and men in the prevalence of alcohol dependence is narrowing,” she said. “One possible explanation is that between 1934 and 1964, the social acceptability of women’s drinking increased. As it was more socially acceptable for women to drink, a greater number of them became drinkers. Because women have a heightened vulnerability to the effects of alcohol – that is, greater blood alcohol levels at similar ‘doses’ of alcohol – we may therefore see a concomitant rise in alcohol dependence among those who ever drank.”

Grucza drew an analogy between women’s drinking habits and culture and immigration. “Clearly there were many changes in the cultural environment for women born in the 40s, 50s and 60s compared to women born earlier,” he said. “Women entered the work force, were more likely to go to college, were less hampered by gender stereotypes, and had more purchasing power. They were freer to engage in a range of behaviors that were culturally or practically off-limits, and these behaviors probably would have included excessive drinking and alcohol problems.”

He noted that U.S. immigrants from cultures with conservative values vis-à-vis drinking tend to adhere to their own cultural norms, while their children are likely to adopt U.S. norms, which are comparatively lax regarding alcohol.

“We can think of U.S. culture as having been traditionally dominated by white men,” added Grucza. “As women have ‘immigrated’ into this culture, they have become ‘acculturated’ with regard to alcohol use. But Black women – who still have the lowest rates of drinking among the demographic groups we looked at – have a second barrier between them and the dominant U.S. culture, namely, their race, that may be keeping them from adopting the standards of the dominant culture with respect to alcohol use.”

Greenfield suggested that specially designed prevention programs that target female drinkers might help to lower drinking rates, and also delay the age of drinking initiation, which could help prevent later alcohol problems. “It would also be helpful to educate women about the gender differences in metabolism of alcohol, and the associated heightened female vulnerability to alcohol’s adverse health consequences at lower doses than men,” she said.

Grucza agreed that interventions for women need further investigation. “Whenever we see change in a disorder in the population, there is an opportunity to take a closer look at which risk factors for the disorder might be changing at the same time,” he said. “The classic example of this would be the rise in lung cancer in the late 20th century, a time in which sales of commercially produced cigarettes also skyrocketed. In this case, we obviously wouldn’t want to change the progress made by women over the last 50 - 60 years, but we can look at specific changes in their drinking behavior and start to speculate about what interventions might work.”

Results are published in the May issue of Alcoholism: Clinical & Experimental Research.