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National Institute on Drug Abuse
Women and Sex/Gender Differences Research
Director's Report to Council
Research Findings Excerpts
February, 1995
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Basic Research |
Marijuana and Genetic Mutations
Researchers at the University of Texas Medical Branch, Galveston, demonstrated a more than three-fold and more than two-fold increase over non-smoking pregnant women in mutations of the hypoxanthine phosphoribosyl transferase (hprt) gene among pregnant women who smoked marijuana and cigarettes, respectively, prior to and early in their pregnancies. Expansion of these preliminary studies should further establish the ability of marijuana to cause genetic mutations in women and the developing fetus (Ammenheuser, MM, Batinson, AB, Babiak, AE, et al. Elevated frequencies of hprt mutant lymphocytes in pregnant women who smoked marijuana, Environmental & Molecular Mutagenesis, 1995, in press).
In a twin study of drug abuse, 4,000 pairs of twins, monozygotic [MZ] and dizygotic [DZ], have been assessed for drug abuse and dependence. Research shows that there is a strong tendency that to a great extent, the abuse of some drugs (cocaine and marijuana) is affected by genetic factors. For marijuana, the common or family environment also made a significant contribution. Initiation of marijuana and cocaine use was influenced by characteristics of the environment (drug availability, peer groups) and the characteristics of the individual (personality). Data suggest that for the continuation of drug use, other individual characteristics, such as physiological and subjective reactions to the drugs, may also be important. Further, among the marijuana users, suspiciousness and agitation appeared to be genetically related, while the pleasant psychological effects appeared to be mediated by the environment shared by twins, and not by genes. Using this twin model, additional studies are underway to examine medical and health, including psychiatric, consequences of drug abuse, and genetic influences on drug use/abuse and associated conduct disorders and antisocial behaviors in childhood and adults. (Tsuang, MT., Llyons, M., Isen, S., Goldberg, J., & True, W. Heritability of initiation and continuation of drug use. Psychiatric Genetics, 1993, 3(3):141; Tsuang, MT., Llyons, M., Goldberg, J., True, W., Meyer J., & Eaves, L. Genetic influences on abuse of illicit drugs: A study of 3,297 twin pairs, submitted to JAMA; Llyons, M., Tooney, R., Green, A., Isen, S., Goldberg, J., True, W., Meyer J., & Tsuang, MT. How do genes influence marijuana use? The role of subjective effects. Submitted to Am. J. Psychiatry.)
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AIDS Research |
HIV, Prenatal Care, and Disease Progression in the Children of HIV-Infected Mothers
In a study attempting to identify health care delivery and clinical factors related to risk of infection and rate of disease progression in the child of an HIV-infected mother (e.g., methadone treatment, level of prenatal care for pregnant HIV-infected women, history of untreated maternal drug abuse, and mother's and child's anti-retroviral and prophylactic drug treatment), analyses of over 2,000 pregnancies have shown that very few HIV-infected women received adequate prenatal care (20% reported no prenatal care and an additional 45% reported too few visits). These findings have important implications for the translation of clinical findings into actual practice, e.g., clinical trial findings of a two-thirds reduction in the rate of mother-to-infant HIV transmission by women treated with zidovudine during pregnancy (with short-term treatment of the infant after delivery). The project has also shown that prenatal care was associated with reduced adverse birth outcomes (e.g., low birth weight and preterm birth). Further analyses are examining associations of health care patterns and clinical factors with the child's clinical course. This study is the largest population of pregnant, HIV-infected women to be analyzed to date, and constitutes the first detailed analysis of prenatal care to be conducted for this population (Turner, BJ; Markson, LE; Hauck, W; et al. Prenatal care of HIV-infected women: Analysis of a large New York State cohort. J Acquir Immune Defic Syndr, 1995, in press.)
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Epidemiologic, Etiology and Prevention Research |
National Pregnancy and Health Survey
Data from the National Pregnancy and Health Survey, found that 5.5 percent, or 221,000 of the 4 million women who gave birth in 1992, used some illicit drug during pregnancy. The survey also estimated that the number of babies born to women who used drugs during pregnancy was 222,000 (a number slightly higher than the number of mothers due to multiple live births). These estimates show that, at some time during their pregnancy, 119,000 women (2.9%) reported use of marijuana and 45,000 women (1.1%) reported use of cocaine; the two most frequently used illicit drugs. The survey also found that 757,000 women (18.8%) used alcohol and 820,000 women (20.4%) smoked cigarettes at some time during pregnancy. Only 6% of those who reported no use of any drug used alcohol and cigarettes during pregnancy, while 32% of those who reported use of one drug also smoked cigarettes and drank alcohol. Conversely, of those who reported no use of alcohol or cigarettes, only 0.2% used marijuana, and 0.1% used cocaine. However, of those who reported use of both alcohol and cigarettes, 20.4% also used marijuana, and 9.5% also used cocaine. This has tremendous public health implications and reinforces the need for health practitioners to continually monitor the status of smoking, drinking and illicit/nonmedical drug use during pregnancy. A final report will be available June 1995.
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