Effects of alcohol on simulated driving and perceived driving impairment in binge drinkers

Background:  Binge drinking (heavy episodic alcohol use) is associated with high rates of impaired driving and myriad alcohol-related accidents. However, the underlying reasons for the heightened accident risk in this demographic group are not known. This research examined acute alcohol effects on simulated driving performance and subjective ratings of intoxication and driving ability in binge and nonbinge drinkers.
Methods:  Young social drinking college students (24 binge drinkers and 16 nonbinge drinkers) participated in this study. Participants attended a session during which they received a moderate dose of alcohol (0.65 g/kg) and a session during which they received a placebo. A simulated driving task measured participants' driving performance in response to each dose. Subjective responses to each dose were also assessed, including ratings of sedation, stimulation, and driving ability.
Results:  The acute dose of alcohol impaired multiple aspects of driving performance in both binge and nonbinge drinkers. Under alcohol, all participants had greater difficulty in maintaining their lane position, maintaining the appropriate speed and made multiple driving errors compared to placebo performance. By contrast, compared with nonbinge drinkers, binge drinkers reported feeling less sedated by the alcohol and reported having a greater ability to drive following the acute dose of alcohol.
Conclusions:  Reduced subjective intoxication and perceived driving impairment in binge drinkers may account for the greater accident risk in this demographic group. Binge drinkers may lack the internal sedation cue that helps them accurately assess that they are not able to effectively drive a vehicle after drinking.     

Acculturation, drinking, and alcohol abuse and dependence among Hispanics in the Texas-Mexico border

Background:  Acculturation has been linked to an increased prevalence of alcohol‐related problems. However, most of the research has been conducted with Hispanic populations in metropolitan areas of the United States, none of which is on the U.S.–Mexico border. This study examines the association between acculturation, heavy episodic drinking, and DSM‐IV alcohol abuse and dependence among Hispanics in the Texas–Mexico border. Methods:  The study used data from a survey conducted (2002 to 2003) along the Texas–Mexico border and included 472 male and 484 female Hispanic adults from El Paso, the Rio Grande Valley, and colonias. Based on the Acculturation Rating Scale for Mexican Americans‐II scale, respondents were coded into 4 acculturation categories: “very Mexican oriented,”“Mexican bicultural,”“Anglo bicultural,” or “very Anglo/Anglicized.”. Results:  Acculturation was related to lower rates of alcohol use disorders among men and a higher frequency of heavy episodic drinking among women. Multivariate analyses indicate that men who report heavy episodic drinking and those who are “very Mexican,”“bicultural Mexican,” or “bicultural Anglo” are more at higher risk for alcohol abuse and/or dependence compared with “very Anglo/Anglicized” men. For women, acculturation level did not predict alcohol disorders. Statistical analyses included testing for bivariate associations and multivariate logistic regression predicting heavy episodic drinking alcohol abuse or dependence. Conclusions:  This study suggests that acculturation has different effects on drinking for men and women. This finding needs some attention as literature also indicates that women drink more and may develop more alcohol‐related problems as they acculturate. This increase in women’s drinking is probably because of U.S. society’s more liberal norms governing female drinking. The “bimodal” distribution of risk, in which only men in “very Anglo” group are at a lower risk than the others, may be unique to the Border. The association between acculturation and alcohol use disorders does not appear to be linear and the effect of acculturation is not uniform on individuals’ drinking behavior.     

Decreased plasma brain-derived neurotrophic factor levels in patients with alcohol dependence

BACKGROUND: Many reports have suggested possible relationships between brain-derived neurotrophic factor (BDNF) and alcohol dependence. A protective effect of BDNF against ethanol-induced cell damage has been suggested, and this effect may contribute to the development or maintenance of alcohol dependence. This study was carried out in order to verify the significance of BDNF in alcohol dependence. METHODS: Peripheral BDNF levels were measured in alcohol-dependent patients and control subjects using an enzyme-linked immunosorbent assay. A physician's interview and standardized questionnaire were used to obtain information regarding each patient's history of alcohol consumption. RESULTS: The mean BDNF level was lower in the alcohol dependence group (389.5 +/- 501.7 pg/ml) than in the normal controls (822.5 +/- 420.7 pg/ml) by analysis of covariance (ANCOVA) (F = 25.79, p < 0.01). The mean BDNF level was lower in the alcohol-dependent patients with a positive family history of alcohol dependence (247.6 +/- 289.2 pg/ml) than in those with a negative family history of alcohol dependence (583.9 +/- 652.8 pg/ml) by ANCOVA (F = 6.51, p = 0.01). The BDNF levels did not correlate significantly with any of the variables analyzed in this study, including Beck depression inventory, state and trait anxiety inventory (STAI-S and T), and various drinking behaviors. CONCLUSIONS: Changes in the levels of BDNF might play a role in the pathophysiology and inheritance of alcohol dependence.     

Patterns of alcohol consumption and alcohol-impaired driving in the United States

Background:  Alcohol-related motor vehicle crashes kill approximately 17,000 Americans annually and were associated with more than $51 billion in total costs in 2000. Relatively little is known about the drinking patterns of alcohol-impaired (AI) drivers in the United States.
Methods:  2006 Behavioral Risk Factor Surveillance System (BRFSS) was analyzed for alcohol consumption and self-reported AI driving among U.S. adults aged ≥18 years for all states. Alcohol consumption was divided into 4 categories: binge/heavy, binge/nonheavy, nonbinge/heavy, and nonbinge/nonheavy. Binge drinking was defined as ≥5 drinks for men or ≥4 drinks for women on one or more occasions in the past month, and heavy drinking was defined as average daily consumption of >2 drinks/day (men) or >1 drink/day (women). The prevalence of AI driving was examined by drinking pattern and by demographic characteristics. Logistic regression analysis was used to assess the association between drinking patterns and AI driving.
Results:  Five percent of drinkers were engaged in AI driving during the past 30 days. Overall, 84% of AI drivers were binge drinkers and 88% of AI driving episodes involved binge drinkers. By drinking category, binge/nonheavy drinkers accounted for the largest percentage of AI drivers (49.4%), while binge/heavy drinkers accounted for the most episodes of AI driving (51.3%). The adjusted odds of AI driving were 20.1 (95% CI: 16.7, 24.3) for binge/heavy, 8.2 (6.9, 9.7) for binge/nonheavy, and 3.9 (2.4, 6.3) for nonbinge/heavy drinkers, respectively.
Conclusions:  There is a strong association between binge drinking and AI driving. Most AI drivers and almost half of all AI driving episodes involve persons who are not heavy drinkers (based on average daily consumption). Implementing effective interventions to prevent binge drinking could substantially reduce AI driving.     

Drinking motives in female smokers: factor structure, alcohol dependence, and genetic influences

Background: Alcohol and tobacco use often co‐occur. Human and animal studies indicate that nicotine increases alcohol’s rewarding effects and the motivation to consume it. The aims of this study were to examine whether the factorial architecture of self‐reported motivations to consume alcohol differed between regular and nonregular cigarette smokers while taking into account the lifetime history of alcohol dependence and psychopathology, and to estimate the genetic and environmental influences on the motivations. Methods: Using data on 2,189 monozygotic and dizygotic female twins, we examined the factorial structure (item thresholds and factor loadings, means, and variances) of the items from the Drinking Motives Questionnaire (DMQ) in regular and nonregular smokers. Post hoc tests examined the association between the latent drinking motives factors and alcohol dependence in both groups. Twin models were fitted to the latent drinking motives factors, testing for variations in the magnitude of additive genetic, shared, and nonshared environmental influences between the groups. Results: The 4 DMQ factors (social, conformity, coping, and enhancement) were recovered in both groups, and their measurement structure was consistent across the groups. Regular smokers reported higher levels of coping, enhancement, and social motives while nonregular smokers reported higher conformity motives. Alcohol dependence was associated with higher scores on all motives in both groups; however, in a regression analysis that included all of the motives as predictor variables, only coping was significantly related to alcohol dependence. While twin models revealed evidence for substantially greater genetic influences on enhancement (h² = 0.40), coping (h² = 0.35) and social (h² = 0.37) drinking motives in regular compared to nonregular smokers, the power to statistically distinguish the 2 groups was low. Conclusions: While the measurement structure of the drinking motive factors appears to be similar across regular and nonregular smokers, regular smokers report more motivation to drink for internal affect‐related reasons and to obtain social reward. Of all the motives, coping was the most robust predictor of alcohol dependence in both the regular and the nonregular smokers. Further, genetic influences might play a larger role in drinking motives among regular smokers, which provides tentative evidence for latent genetic × smoking status interactions.     

Possible role of nerve growth factor in the pathogenesis of alcohol dependence

BACKGROUND: Recent studies have raised the possibility that nerve growth factor (NGF) is abnormally regulated in the central nervous system (CNS) of animal models of chronic ethanol treatment. The goals of this study were to determine whether prolonged alcohol consumption is associated with the plasma NGF levels and to assess the effect of a positive family history of alcohol dependence on plasma NGF levels in the alcohol-dependent patients. METHODS: We used the enzyme-linked immunosorbent assay (ELISA) to determine the concentrations of peripheral NGF in patients with alcohol dependence and in a control group. RESULTS: The plasma NGF concentrations in the alcohol-dependent patients were significantly lower than in the controls (71.9 vs 110.5 pg/mL, respectively). Moreover, the alcohol-dependent patients with positive family histories showed a greater decrease in their NGF levels than those subjects with negative family histories (64.7 vs 83.3 pg/mL, respectively). CONCLUSIONS: Our study suggests that the NGF levels may be a trait marker for the development of alcohol dependence.     

Adult transition from at-risk drinking to alcohol dependence: the relationship of family history and drinking motives

Background:  Prospective studies have not previously examined whether a family history of alcoholism and drinking motives conjointly predict a diagnosed DSM-IV alcohol abuse or dependence in adults, despite a large literature that each is associated with alcohol consumption. The focus of this study is the conjoint, prospective examination of these risk factors in a 10-year longitudinal study of adults who were at-risk drinkers at baseline.
Methods:  Prospective, population-based cohort of drinkers aged 18 or older from a Northeastern U.S. area initially evaluated for history of alcohol use disorders and drinking motives in 1991 to 1992. New onset dependence was studied in those who never met the criteria for alcohol dependence at baseline ( n  = 423), and new onset abuse was studied in those who never met the criteria for alcohol abuse at baseline ( n  = 301) and who did not develop dependence during the follow-up.
Results:  Family history significantly interacted with 2 baseline drinking motives in predicting new onsets of DSM-IV alcohol dependence: drinking to reduce negative affect (OR 3.38; 95% CI 1.05, 10.9) and drinking for social facilitation (OR 3.88; CI 1.21, 12.5). Effects were stronger after conditioning the drinking motives on having a positive family history of alcoholism. In contrast, in predicting new onsets of alcohol abuse, drinking motives did not have direct effects or interact with family history.
Conclusions:  Those who drank to reduce negative affect or for social facilitation at baseline were at greater risk of alcohol dependence 10 years later if they also had a family history of alcoholism. These results suggest an at-risk group that can be identified prior to the development of alcohol dependence. Further, the findings suggest utility in investigating the interaction of drinking motives with measured genetic polymorphisms in predicting alcohol dependence.     

A 6-month controlled naltrexone study: combined effect with cognitive behavioral therapy in outpatient treatment of alcohol dependence

BACKGROUND: In several studies, patients with alcohol dependence treated with the opioid antagonist naltrexone have shown fewer relapses to heavy drinking than those receiving placebo. An interaction between the naltrexone effect and the type of psychological therapy has been observed. METHODS: A 6-month, double-blind, placebo-controlled, parallel-group study was performed at 10 different investigation sites. After a placebo run-in period of 1 week, 118 patients were randomized into 4 treatment groups-50 mg of naltrexone daily or placebo in combination with either cognitive behavioral therapy (CBT) or supportive therapy. The CBT was performed over nine sessions according to the manual of Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity). The supportive therapy was defined as "the treatment as usual." Alcohol consumption, craving, carbohydrate-deficient transferrin, medication compliance by tablet count, and adverse clinical events were assessed at all visits. Other liver enzymes and psychiatric symptoms were also determined. RESULTS: Ninety-one (77%) patients completed the study, and 92 (78%) were 80% compliant with the medication regimen. A lower percentage of heavy-drinking days was shown in the naltrexone group (p = 0.045) compared with the placebo group, as was a lower craving score (p = 0.029). These results are supported by the lower levels of liver enzyme activities (p < 0.010 for aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase), but not by the carbohydrate-deficient transferrin levels, in the naltrexone group. The mean time period before the first day of heavy drinking was longer for the group treated with CBT (p = 0.010), especially in combination with naltrexone (p = 0.007). Naltrexone was well tolerated, and no patients discontinued the study due to side effects. CONCLUSIONS: This study supports the effect of naltrexone in outpatient treatment of alcohol dependence and suggests that a beneficial interaction effect with CBT can be expected.     

Efficacy of extended-release naltrexone in patients with relatively higher severity of alcohol dependence

Background: Because some literature reviews have suggested that naltrexone’s benefit may be limited to less‐severe alcohol dependence, and exclusively to reduction in heavy drinking rather than abstinence, we examined the efficacy of once per month, injectable extended‐release naltrexone (XR‐NTX 380 mg) in patients with relatively higher severity alcohol dependence. Methods: Post hoc analyses examined data from a multicenter, placebo‐controlled, 24‐week randomized trial of XR‐NTX for alcohol dependence (N = 624). We analyzed treatment effects in alcohol‐dependent patients who had higher baseline severity, as measured by: (i) the Alcohol Dependence Scale (ADS) or (ii) having been medically detoxified in the week before randomization. Efficacy was also examined via the relationship between pretreatment severity indices and reporting at least 4 days of lead‐in abstinence prior to treatment—a major predictor of good outcome in the original study. Results: Higher severity alcohol‐dependent patients, defined by the ADS, when receiving XR‐NTX 380 mg (n = 50) compared with placebo (n = 47), had significantly fewer heavy‐drinking days in‐trial (hazard ratio=0.583; p = 0.0049) and showed an average reduction of 37.3% in heavy‐drinking days compared with 27.4% for placebo‐treated patients (p = 0.039). Among those who had a detoxification just prior to randomization, these reductions were 48.9% (XR‐NTX 380 mg; n = 11) and 30.9% (placebo; n = 15) (p = 0.004). Subjects with at least 4 days of pretreatment abstinence (n = 82) versus those without (n = 542) had significantly higher pretreatment ADS scores (p = 0.002) and were more likely to require detoxification prior to randomization (p < 0.001). Patients with lead‐in abstinence experienced significantly better maintenance of initial and 6‐month abstinence. Conclusions: These secondary analyses support the efficacy of XR‐NTX 380 mg in relatively higher severity alcohol dependence for both reduction in heavy drinking and maintenance of abstinence, with implications for the role of adherence pharmacotherapy.     

Factor Structure and Concurrent Validity of the Obsessive Compulsive Drinking Scale in a Group of Alcohol-Dependent Subjects of Mexico City

Background:  Obsessive thoughts and compulsive drinking behaviors have been proposed as key factors associated with the loss of control over alcohol consumption experienced by alcohol-dependent patients. The self-report 14-item Obsessive Compulsive Drinking Scale (OCDS; Anton et al., 1995 ) was designed in order to rate these features.
Methods:  A Spanish-translated version of the OCDS was applied to a group of 159 alcohol-dependent subjects while in abstinence, and data were analyzed in order to evaluate the factor structure and concurrent validity of the scale.
Results:  Several solutions were explored after applying the principal factor analysis to the data. The most plausible result was obtained after excluding the items on quantity and frequency of drinking. This model explaining 56.9% of the variance included 2 factors: obsessive thoughts related to drinking and interference/behaviors related to drinking. Additionally, OCDS scores were significantly correlated with measures for the Alcohol Dependence Scale, number of DSM-IV criteria met for alcohol dependence as well as the number of days in a week engaged in heavy drinking, indicating concurrent validity.
Conclusions:  Our results support the use of OCDS as a valid self-rated instrument that can be broadly applied in research and treatment settings. However, its current version includes questions that may not represent the core concept of craving. The abridged 12-item version of the scale (excluding the items on drinking habits) maintains good psychometrics features and seems to be adequate when different cognitive and behavioral dimensions are explored.     

Cigarette smoking and the risk for alcohol use disorders among adolescent drinkers

BACKGROUND: Cigarette smoking and alcohol use disorders (AUDs) are closely linked, but it is not clear whether higher rates of AUD among smokers are solely attributable to heavier drinking or, alternatively, whether smokers are more vulnerable to alcohol abuse and dependence than nonsmokers who drink comparable quantities. We sought to address this issue using data from a nationally representative U.S. sample of adolescents and young adults. Specifically, we analyzed the relationship between cigarette smoking, drinking, and AUDs. METHODS: Data were from the aggregated 2002 through 2004 U.S. National Survey on Drug Use and Health. Participants were randomly selected, household-dwelling adolescents and young adults (ages 12-20) from the noninstitutionalized, civilian population of the United States (N=74,836). Measurements included current DSM-IV alcohol abuse or dependence, number of drinks in the past 30 days, and past-year cigarette smoking, defined as having smoked more than 100 cigarettes across the lifetime and having smoked during the past year. RESULTS: Past-year smokers (prevalence=16.0%) drank in higher quantities than never-smokers, but were also at elevated risk for AUD when compared with never-smokers who drank equivalent quantities. The effect was observed across age groups, but was more prominent among younger adolescents. After adjusting for drinking quantity and sociodemographic variables, smokers had 4.5-fold higher odds of AUD than never-smokers [95% confidence interval (95% CI), 3.1-6.6]. Youths who reported smoking but did not cross the 100-cigarette threshold were at intermediate risk [odds ratio (OR), 2.3; 95% CI, 1.7-3.3]. Differences in AUD between smokers and never-smokers were most pronounced at lower levels of drinking. CONCLUSIONS: The results are consistent with a higher vulnerability to AUDs among smokers, compared with nonsmokers who drink equivalent quantities.     

A comparison of correlates of DSM-IV alcohol abuse or dependence among more than 400 sons of alcoholics and controls

BACKGROUND: Alcohol dependence and abuse are defined as separate disorders. However, relatively few data are available about whether the same characteristics predict both syndromes. METHODS: Complete data were available from the 15 year follow-up of 411 men who originally had been evaluated from a university population at about age 20. Both baseline data gathered prospectively and the retrospective ratings in six domains of life functioning were analyzed for their relationship to the development of alcohol abuse or dependence during the follow-up. RESULTS: Baseline characteristics of a family history of substance use disorders, the quantity and frequency of drinking, the history of alcohol-related problems, and the level of response to alcohol all predicted future alcohol abuse or dependence, but only an alcoholic second-degree relative or a first-degree drug-dependent family member differentially predicted dependence. Logistic regression analyses revealed that similar baseline characteristics combined to predict dependence and, separately, abuse. When the domains of functioning during the 15 years were included, positive alcohol expectancies, poor coping mechanisms, low level of social support, and drinking in the environment contributed to both dependence and abuse, although the relationship was stronger for dependence. CONCLUSIONS: The predictors and correlates of alcohol abuse and dependence in this group of men were similar. Further research in additional populations and on other drugs is needed to determine if the two syndromes overlap sufficiently to be combined.     

Alterations of brain-derived neurotrophic factor serum levels in patients with alcohol dependence

Background: Alcohol dependence is a chronic relapsing disorder characterized by repetitive alcohol drinking patterns and a loss of control over alcohol consumption. Recent studies have hypothesized that dysregulations in brain neurotrophic support regulated by neurotrophins may be involved in the vulnerability to dependence and in the brain damage caused by chronic alcohol consumption. The neurotrophin brain‐derived neurotrophic factor (BDNF) plays a pivotal role in neurodevelopment and in the maintenance of adult brain homeostasis through the regulation of neurogenesis and neuronal plasticity. The role of BDNF and its signaling in the mechanisms of alcohol dependence has been well documented in studies of animal models, but a few studies have been conducted in human peripheral tissues. On the basis of this rationale, we compared BDNF levels in both serum and plasma in alcohol‐dependent patients and healthy volunteers. Methods: Thirty‐seven patients with a principal diagnosis of alcohol dependence were recruited. In parallel, a control group of 37 unrelated volunteers matched for gender and age was enrolled. Serum and plasma BDNF levels were measured by ELISA. Results: A significant reduction in BDNF serum levels was observed in the patient group compared to healthy subjects (p = 0.028). On the contrary, no difference in BDNF plasma levels was evident between patients and controls. Conclusions: In conclusion, our data show an alteration of BDNF peripheral content in patients with alcohol dependence, suggesting the involvement of this neurotrophin in this psychopathology.     

The five-year predictive validity of each of the seven DSM-IV items for alcohol dependence among alcoholics

BACKGROUND: Information about the prognostic implications of a DSM-IV diagnosis of alcohol dependence is important to both clinicians and researchers. In this regard, only limited data are available on the performance of specific diagnostic items. METHODS: This study reports data gathered with a structured, validated interview with 642 alcohol-dependent men and women from the Collaborative Study of the Genetics of Alcoholism (COGA). The goals were to evaluate the ability of each of the DSM-IV dependence items to predict the occurrence over the next 5 years of a broad pattern of 27 alcohol-related problems. For comparison, similar data are reported regarding the performance of abuse criteria for 516 additional subjects. RESULTS: The results revealed that dependence item 3 (use of alcohol in larger amounts) was the only criterion that did not relate significantly to outcome, and indicated that the dependence criteria related relatively similarly to different types of outcomes among alcoholics. No specific combination of diagnostic items stood out in predicting outcome but, rather, the span of items generally performed well. CONCLUSIONS: These data support the potential usefulness of the DSM-IV dependence criteria.     

Rates and correlates of relapse among individuals in remission from DSM-IV alcohol dependence: a 3-year follow-up

Background: There is little information on the stability of abstinent and nonabstinent remission from alcohol dependence in the general U.S. population. The aim of this study was to examine longitudinal changes in recovery status among individuals in remission from DSM‐IV alcohol dependence, including rates and correlates of relapse, over a 3‐year period. Methods: This analysis is based on data from Waves 1 and 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a nationally representative sample of U.S. adults aged 18 years and older originally interviewed in 2001 to 2002 and reinterviewed in 2004 to 2005. The Wave 1 NESARC identified 2,109 individuals who met the DSM‐IV criteria for full remission from alcohol dependence. Of these, 1,772 were reinterviewed at Wave 2, comprising the analytic sample for this study. Recovery status at Wave 2 was examined as a function of type of remission at Wave 1, with a focus on rates of relapse, alternately defined as recurrence of any alcohol use disorder (AUD) symptoms and recurrence of DSM‐IV alcohol dependence. Logistic regression models were used to estimate the odds of relapse among asymptomatic risk drinkers and low‐risk drinkers relative to abstainers, adjusted for a wide range of potential confounders. Results: By Wave 2, 51.0% of the Wave 1 asymptomatic risk drinkers had experienced the recurrence of AUD symptoms, compared with 27.2% of low‐risk drinkers and 7.3% of abstainers. Across all ages combined, the adjusted odds of recurrence of AUD symptoms relative to abstainers were 14.6 times as great for asymptomatic risk drinkers and 5.8 times as great for low‐risk drinkers. The proportions of individuals who had experienced the recurrence of dependence were 10.2, 4.0, and 2.9%, respectively, and the adjusted odds ratios relative to abstainers were 7.0 for asymptomatic risk drinkers and 3.0 for low‐risk drinkers. Age significantly modified the association between type of remission and relapse. Differences by type of remission were not significant for younger alcoholics, who had the highest rates of relapse. Conclusions: Abstinence represents the most stable form of remission for most recovering alcoholics. Study findings highlight the need for better approaches to maintaining recovery among young adults in remission from alcohol dependence, who are at particularly high risk of relapse.     

A National Survey of Adult Asthma Prevalence by Urban-Rural Residence U.S. 2005

Objectives. We analyzed national data to estimate asthma prevalence among U.S. adults by urban-rural residence and to determine the relative contributions of sociodemographic and health behavior characteristics on the probability of reporting asthma. Methods. We linked the 2005 Behavioral Risk Factor Surveillance System (BRFSS) to Urban Influence Codes (UICs), categorizing respondents into four urban-rural groups: metropolitan, adjacent metropolitan, micropolitan, and remote. BRFSS collects health data from all 50 states. UICs classify respondent's county as urban or rural based on population size and proximity to metropolitan areas. We calculated asthma prevalence estimates and generated odds ratios (ORs) for the probability of reporting asthma. Results. Overall asthma prevalence (7.9%; 95%CI = 7.73–8.08) was not statistically different (p = 0.28) by urban-rural residence. After adjusting for selected characteristics, adjacent metropolitan (OR = 0.96; 95%CI = 0.90–1.02) and remote (OR = 0.95; 95%CI = 0.85–1.05) residents were less likely—and micropolitan (OR = 1.04; 95%CI = 0.93–1.16) residents were more likely—to report asthma compared with metropolitan residents; but confidence intervals included null. Conclusions. Asthma prevalence is as high in rural as in urban areas. Certain demographic, behavioral, and health care characteristics unique to place of residence might affect asthma prevalence. Because these results substantially change our understanding of asthma prevalence in rural areas, further investigation is needed to determine geographic-related risk factors     

The genetics of alcohol intake and of alcohol dependence

BACKGROUND: Because alcohol has multiple dose-dependent consequences, it is important to understand the causes of individual variation in the amount of alcohol used. The aims of this study were to assess the long-term repeatability and genetic or environmental causes of variation in alcohol intake and to estimate the degree of overlap with causes of susceptibility to alcohol dependence. METHODS: Data were used from three studies conducted between 1980 and 1995 on volunteer adult male and female Australian twin subjects. In each study, alcohol intake was reported both as quantity x frequency and as past-week data. Repeatability was calculated as correlations between occasions and between measures, and the effects of genes and environment were estimated by multivariate model fitting to the twin pair repeated measures of alcohol use. Relationships between mean alcohol use and the lifetime history of DSM-III-R alcohol dependence were tested by bivariate model fitting. RESULTS: Repeatability of the alcohol intake measures was between 0.54 and 0.85, with the highest repeatability between measures within study and the lowest repeatability between the first and last studies. Reported alcohol consumption was mainly affected by genetic factors affecting all times of study and by nonshared environmental factors (including measurement error) unique to each time of study. Genes that affect alcohol intake do affect alcohol dependence, but genetic effects unique to dependence are also significant; environmental effects are largely unique to either intake and dependence. CONCLUSIONS: Nearly all the repeatable component of variation in alcohol intake is due to genetic effects. Genes affecting intake also affect dependence risk, but there are other genes that affect dependence alone. Studies aiming to identify genes that affect alcohol use disorders need to test loci and candidate genes against both phenotypes.