Genome-Wide and Candidate Gene Association Study of Cigarette Smoking Behaviors

The contribution of common genetic variation to one or more established smoking behaviors was investigated in a joint analysis of two genome wide association studies (GWAS) performed as part of the Cancer Genetic Markers of Susceptibility (CGEMS) project in 2,329 men from the Prostate, Lung, Colon and Ovarian (PLCO) Trial, and 2,282 women from the Nurses' Health Study (NHS). We analyzed seven measures of smoking behavior, four continuous (cigarettes per day [CPD], age at initiation of smoking, duration of smoking, and pack years), and three binary (ever versus never smoking, ≤10 versus >10 cigarettes per day [CPDBI], and current versus former smoking). Association testing for each single nucleotide polymorphism (SNP) was conducted by study and adjusted for age, cohabitation/marital status, education, site, and principal components of population substructure. None of the SNPs achieved genome-wide significance (p<10−7) in any combined analysis pooling evidence for association across the two studies; we observed between two and seven SNPs with p<10−5 for each of the seven measures. In the chr15q25.1 region spanning the nicotinic receptors CHRNA3 and CHRNA5, we identified multiple SNPs associated with CPD (p<10−3), including rs1051730, which has been associated with nicotine dependence, smoking intensity and lung cancer risk. In parallel, we selected 11,199 SNPs drawn from 359 a priori candidate genes and performed individual-gene and gene-group analyses. After adjusting for multiple tests conducted within each gene, we identified between two and five genes associated with each measure of smoking behavior. Besides CHRNA3 and CHRNA5, MAOA was associated with CPDBI (gene-level p<5.4×10−5), our analysis provides independent replication of the association between the chr15q25.1 region and smoking intensity and data for multiple other loci associated with smoking behavior that merit further follow-up

Genome-Wide and Candidate Gene Association Study of Cigarette Smoking Behaviors

The contribution of common genetic variation to one or more established smoking behaviors was investigated in a joint analysis of two genome wide association studies (GWAS) performed as part of the Cancer Genetic Markers of Susceptibility (CGEMS) project in 2,329 men from the Prostate, Lung, Colon and Ovarian (PLCO) Trial, and 2,282 women from the Nurses' Health Study (NHS). We analyzed seven measures of smoking behavior, four continuous (cigarettes per day [CPD], age at initiation of smoking, duration of smoking, and pack years), and three binary (ever versus never smoking, ≤10 versus >10 cigarettes per day [CPDBI], and current versus former smoking). Association testing for each single nucleotide polymorphism (SNP) was conducted by study and adjusted for age, cohabitation/marital status, education, site, and principal components of population substructure. None of the SNPs achieved genome-wide significance (p<10−7) in any combined analysis pooling evidence for association across the two studies; we observed between two and seven SNPs with p<10−5 for each of the seven measures. In the chr15q25.1 region spanning the nicotinic receptors CHRNA3 and CHRNA5, we identified multiple SNPs associated with CPD (p<10−3), including rs1051730, which has been associated with nicotine dependence, smoking intensity and lung cancer risk. In parallel, we selected 11,199 SNPs drawn from 359 a priori candidate genes and performed individual-gene and gene-group analyses. After adjusting for multiple tests conducted within each gene, we identified between two and five genes associated with each measure of smoking behavior. Besides CHRNA3 and CHRNA5, MAOA was associated with CPDBI (gene-level p<5.4×10−5), our analysis provides independent replication of the association between the chr15q25.1 region and smoking intensity and data for multiple other loci associated with smoking behavior that merit further follow-up

Importance of a standard unit dose for cannabis research.

Commentary: Recognizing the increasing diversity of cannabis products and their expanded use, Freeman & Lorenzetti propose a standard unit dose of 5 mg 9‐tetrahydrocannabinol (THC) to be used for all cannabis products, regardless of method of administration. They argue that a standard dose would help to guide consumers towards safer patterns of cannabis use. The National Institute on Drug Abuse (NIDA) strongly supports the need for a standardized measure to facilitate research, and this was a key recommendation from NIDA's Cannabis Policy Research Council Workgroup...

Drugs of abuse and the aging brain

Substance abuse among older adults has received little attention in the past, presumably because this population has traditionally accounted for only a small percentage of the drug abuse problem in the United States. The aging of the baby boomer generation (born 1946-1964), however, will soon swell the ranks of older adults and dramatically alter the demography of American society. Several observations suggest that this expansion will likely be accompanied by a precipitous increase in the abuse of drugs, including prescription medications and illicit substances, among older adults. While it is now evident that the brain changes continuously across life, how drugs of abuse interact with these age-related changes remains unclear. The dynamic nature of brain function, however, suggests that substance abuse during older age may augment the risks and require unique considerations for diagnosis and treatment. In addition to describing current and projected prevalence estimates of substance abuse among older adults, the present review discusses how aging affects brain systems involved in drug abuse, and explores the potential impact of drug abuse on the aging brain. Future directions for substance abuse research among older adults will also be considered

Patient Decision to Initiate Therapy for Osteoporosis: The Influence of Knowledge and Beliefs

BACKGROUND: There are effective treatments to prevent osteoporotic fractures, but these treatments are underutilized. OBJECTIVE: To evaluate the influence of patient characteristics, perceptions, knowledge and beliefs about osteoporosis on the decision to initiate osteoporotic treatment. PARTICIPANTS: We identified female members of a managed care plan who had a dual energy x-ray absorptiometry (DXA) bone density test and fulfilled World Health Organization criteria for osteoporosis. Patients were excluded if they received osteoporotic medications in the prior 6 months. MEASUREMENTS: Patients were sent a questionnaire that included items assessing satisfaction with physician-patient communication, trust in the physician, osteoporosis knowledge and beliefs, beliefs about prescription medications, and perceptions of barriers to medication use. Administrative electronic health records were used to identify prescription drug use and health care utilization. RESULTS: Two hundred and thirty-six women returned surveys and research authorization forms out of 465 contacted for participation. One hundred and thirty-five (57.2%) filled a prescription for an osteoporotic drug in the first 3 months after the DXA exam. The largest differences between initiators and non-initiators were in beliefs in the benefits of medications, and distrust of medications, with initiators believing more strongly in the benefits and effectiveness of medications (p \u3c .001), and non-initiators reporting more distrust of medications (p \u3c .001). Osteoporosis knowledge and the belief that osteoporosis is a serious disease were also related to therapy initiation in bivariate analysis. CONCLUSIONS: Only 57% of patients initiated osteoporotic medication within 3 months of diagnosis. The decision to start osteoporosis treatment appeared to be related to a patient\u27s beliefs in the effectiveness of osteoporosis medications and distrust of medications

Limited Literacy and Mortality in the Elderly: The Health, Aging, and Body Composition Study

BACKGROUND: While limited literacy is common and its prevalence increases with age, no prospective study has assessed whether limited literacy is associated with mortality in older adults. OBJECTIVE: To assess the association of limited literacy with mortality. DESIGN AND SETTING: Five-year prospective study from 1999 to 2004 of community-dwelling elders from Memphis, TN, and Pittsburgh, PA, who were from the Health, Aging, and Body Composition study. Subjects' literacy was assessed with the Rapid Estimate of Adult Literacy in Medicine. Scores were categorized into limited (0 to 8th grade reading level) or adequate literacy (≥9th grade reading level). PARTICIPANTS: Two thousand five hundred and twelve black and white elders without baseline functional difficulties or dementia. MEASUREMENTS: Time to death. RESULTS: Participants' mean age was 75.6 years, 48% were male, 38% were black, and 24% had limited literacy; the median follow-up time was 4.2 years. Compared with those with adequate literacy, those with limited literacy had a higher risk of death (19.7% vs 10.6%) with a hazard ratio (HR) of 2.03 (95% confidence intervals [CI], 1.62 to 2.55). After adjusting for demographics and socioeconomic status, co-morbid conditions, self-rated health status, health-related behaviors, health care access measures, and psychosocial status, limited literacy remained independently associated with mortality (HR 1.75; 95% CI, 1.27 to 2.41). CONCLUSIONS: Limited literacy is independently associated with a nearly 2-fold increase in mortality in the elderly. Given the growth of the aging population and the prevalence of chronic diseases, the mechanisms by which limited literacy is associated with mortality in the elderly warrant further investigation