Increased caffeinated coffee consumption has now been shown to be associated with decreased risk of depression in women. The risk of depression appears to decrease for women with increasing consumption of caffeinated coffee, according to a report in the September 26 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Caffeine is the most frequently used central nervous system stimulant in the world, and approximately 80 percent of consumption is in the form of coffee, according to background information in the article. Previous research, including one prospective study among men, has suggested an association between coffee consumption and depression risk. Because depression is a chronic and recurrent condition that affects twice as many women as men, the authors sought to examine whether, in women, consumption of caffeine or certain caffeinated beverages is associated with the risk of depression.
Michel Lucas, Ph.D., R.D., from the Harvard School of Public Health, Boston, and colleagues studied 50,739 U.S. women who participated in the Nurses’ Health Study. Participants, who had a mean (average) age of 63, had no depression at the start of the study in 1996 and were prospectively followed up with through June 2006. Researchers measured caffeine consumption through questionnaires completed from May 1980 through April 2004, including the frequency that caffeinated and noncaffeinated coffee, nonherbal tea, caffeinated soft drinks (sugared or low-calorie colas), caffeine-free soft drinks (sugared or low-calorie caffeine-free colas or other carbonated beverages) and chocolate were usually consumed in the previous 12 months. The authors defined depression as reporting a new diagnosis of clinical depression and beginning regular use of antidepressants in the previous two years.
When compared with women who consumed one cup of caffeinated coffee or less per week, those who consumed two to three cups per day had a 15 percent decrease in relative risk for depression, and those consuming four cups or more per day had a 20 percent decrease in relative risk. Compared with women in the lowest (less than 100 milligrams [mg] per day) categories of caffeine consumption, those in the highest category (550 mg per day or more) had a 20 percent decrease in relative risk of depression. No association was found between intake of decaffeinated coffee and depression risk.
“In this large prospective cohort of older women free of clinical depression or severe depressive symptoms at baseline, risk of depression decreased in a dose-dependent manner with increasing consumption of caffeinated coffee,” write the authors.