Alcohol consumption and health status of family members: health impacts without ingestion

Alcohol use disorder hospitalisations over the last two decades: a population-based cohort study

BACKGROUND

Alcohol use disorders are risk factors for almost all health conditions due to heavy alcohol use. The epidemiology of alcohol use disorders can be used to monitor harm from heavy alcohol consumption.

AIM

To estimate changes in the risk of alcohol use disorders over the last two decades among the Western Australian adult population.

METHODS

This population-based cohort study used hospital separation records for Western Australian residents aged 18 years and older that occurred between 1990 and 2013 with a primary diagnosis of alcohol use disorder and annual estimated residential population to estimate the annual gender- and age-specific incidence rate. A random sample of emergency presentations to public hospitals in Western Australia between 2002 and 2013 was used to account for confounding effects, such as changes in patient access to medical care and overall improvement in healthcare service in the multivariable Poisson regression model.

RESULTS

The risk of alcohol use disorder hospitalisations among the Western Australia population has increased considerably since 1998 with a decline in 2012 and 2013. The average rate remained significantly higher from 2010 to 2013 compared with previous years.

CONCLUSIONS

The trend of alcohol use disorder hospitalisations is indicative of an increase in harm due to heavy alcohol use in the population.

Examining the Relationship between Heavy Alcohol Use and Assaults: With Adjustment for the Effects of Unmeasured Confounders

BACKGROUND

Experimental studies suggest that alcohol can lead to aggression in laboratory settings; however, it is impossible to test the causal relationship between alcohol use and real-life violence among humans in randomized clinical trials. Objectives. (i) To examine the relationship between heavy alcohol use and assaults in a population based study; (ii) to demonstrate the proxy outcome method, as a means of controlling the effects of unknown/unmeasured confounders in observational studies.

METHODS

This study used data collected from three waves of the National Survey on Drug Use and Health (NSDUH). The effects of heavy alcohol use on assault were measured using multivariable logistic regressions in conjunction with the proxy outcome method.

RESULTS

Application of the proxy outcome method indicated that effect sizes of heavy alcohol use on the risk of assault were overestimated in the standard models. After adjusting for the effects of unknown/unmeasured confounders, the risk of assault remained 43% and 63% higher (P < 0.05) among participants who consumed 5+ drinks/day for 5-8 days/month and 9-30 days/month, respectively.

CONCLUSIONS

Even after adjustment for unknown/unmeasured confounders the association between heavy alcohol use and risk of violence remained significant. These findings support the hypothesis that heavy alcohol use can cause violence.

Age at first use of alcohol predicts the risk of heavy alcohol use in early adulthood: a longitudinal study in the United States

BACKGROUND

Two ecological cross-sectional studies which relied on national survey data (U.S. and Australia) have shown that starting drinking at a younger age increases the frequency of heavy drinking in the general population, including those with good mental and physical health status. This study further investigates the hypothesis that age at first use of alcohol increases the risk of heavy alcohol use by applying data from a longitudinal study.

METHOD

This study used public-use data collected from Wave I, Wave III and Wave IV of the National Longitudinal Study of Adolescent Health in the United States. The association between age at first use of alcohol and heavy alcohol use (5+ drinks per occasion) was examined with two different multivariate analysis approaches with data from 2316 participants: ordered logistic regression models and Poisson regression models with longitudinal data settings. In addition, the newly developed proxy outcome approach was further used to estimate and adjust for unmeasured/unobserved confounding factors.

RESULTS

Age at first use of alcohol before 18 years was associated significantly higher risk of heavy alcohol use at follow-up.

CONCLUSION

After adjusting for known and residual confounders, younger age at first use of alcohol was associated with significantly higher risk of heavy alcohol use, moreover, we posit that the association observed from this longitudinal study is probably causal. Abstinence from alcohol until the age of 18 years will likely reduce individual risk of alcohol-related problems in adulthood. In the longer term, delayed onset of exposure with widespread abstinence among this age group is also likely to reduce the overall prevalence of alcohol-related problems in the general population.

Alcohol consumption during adolescence and risk of diabetes in young adulthood

Background. There is very limited data available on the association between underage drinking and risk of diabetes. The aim of this study is to investigate the association between alcohol use during adolescence and the risk of diabetes while controlling for a wide range of confounders, including parental alcohol use. Methods. This population-based study used data collected from the National Longitudinal Study of Adolescent Health (Add Health). Participants were initially recruited in 1994-1995 (Wave I), then followed up in 1996 (Wave II) and in 2001-2002 (Wave III), and in 2008-2009 (Wave IV). Analysis included 2,850 participants (46% male) who were successfully followed up at Waves I, III, and IV without a known diagnosis of diabetes at Waves I and III and who provided all necessary information for the analysis. Results. During adolescence, frequent alcohol consumption at levels reaching 5 or more drinks, 3–7 days/week, substantially increased the risk of diabetes in young adulthood, with an odds ratio of 12.57 (95% CI 4.10–38.61) compared to current abstainers. Conclusions. Heavy alcohol use during adolescence may increase the risk of diabetes in young adulthood. The Significant finding of the Study.

A proxy outcome approach for causal effect in observational studies: a simulation study

BACKGROUND

Known and unknown/unmeasured risk factors are the main sources of confounding effects in observational studies and can lead to false observations of elevated protective or hazardous effects. In this study, we investigate an alternative approach of analysis that is operated on field-specific knowledge rather than pure statistical assumptions.

METHOD

The proposed approach introduces a proxy outcome into the estimation system. A proxy outcome possesses the following characteristics: (i) the exposure of interest is not a cause for the proxy outcome; (ii) causes of the proxy outcome and the study outcome are subsets of a collection of correlated variables. Based on these two conditions, the confounding-effect-driven association between the exposure and proxy outcome can then be measured and used as a proxy estimate for the effects of unknown/unmeasured confounders on the outcome of interest. Performance of this approach is tested by a simulation study, whereby 500 different scenarios are generated, with the causal factors of a proxy outcome and a study outcome being partly overlapped under low-to-moderate correlations.

RESULTS

The simulation results demonstrate that the conventional approach only led to a correct conclusion in 21% of the 500 scenarios, as compared to 72.2% for the alternative approach.

CONCLUSION

The proposed method can be applied in observational studies in social science and health research that evaluates the health impact of behaviour and mental health problems.

An investigation of the significance of residual confounding effect

Background. Observational studies are commonly conducted in health research. However, due to their lack of randomization, the estimated associations between the outcome and the exposure can be affected by unmeasured confounding factors. It is important to determine how likely a significant association observed between an outcome variable and a noncausally related exposure may be introduced by residual confounding factors. Methods. A simulation approach is developed based on the sufficient cause model to test the likelihood of significant associations observed between a noncausally related exposure and the outcome. Results. Based on the estimates from all 500 replicates, the association between the exposure and the outcome is found to be significant in 386 (77%) replicates when all confounders (component causes) are controlled for in the model. However, when a subset of real component causes and some noncausal factors are controlled for in the model, the association between exposure and the outcome becomes significant in 487 (97%) replicates. Conclusion. Even when all confounding factors are known and controlled for using conventional multivariate analysis, the observed association between exposure and outcome can still be dominated by residual confounding effects. Therefore, an observed significant association apparently provides limited evidence for a causal relationship.

Age at first use of alcohol and risk of heavy alcohol use: a population-based study

AIM

To examine the association between age at first alcohol use and risk of heavy alcohol use among the adult US general drinking population.

METHODS

This population-based study used the 2010 National Survey on Drug Use and Health (NSDUH) from United States. Multivariate Poisson regression was employed to predict the frequency of heavy alcohol use (five or more drinks per occasion) in the last 30 days with age at first use of alcohol controlling for potential confounding factors.

RESULTS

Younger age at first use of alcohol was associated with increased likelihood of heavy alcohol use in the last 30 days in this population-based sample. This association remained significant when analysis was reperformed for the subgroup of participants who were with desired good health status and Kessler score lower than 12.

CONCLUSION

Younger age at first use of alcohol was associated with increased likelihood of heavy alcohol use.

Observational research on alcohol use and chronic disease outcome: new approaches to counter biases

BACKGROUND

The frequently reported protective effects of moderate alcohol consumption in observational studies may be due to unadjusted bias.

AIM

To examine two new approaches that account for unknown confounding factors and allow the application of intention-to-treat analysis.

METHOD

This study used data from the 2008, 2009, and 2010 National Health Interview Surveys conducted in the United States. Unknown confounding effects were estimated through the association between parental alcohol use and health outcomes for children, because the presence of hypothetical physiological effects of alcohol can be ruled out for this association. In order to apply intention-to-treat analysis, previous alcohol use of former drinkers was obtained by using multiple imputations. Estimates with new adjustment approaches were compared with the traditional approach.

RESULTS

The traditional analytical approach; appears to be consistent with findings from previous observational studies; when two further adjustment approaches were used, the "protective" effects of moderate drinking almost disappeared.

CONCLUSION

Use of a proxy outcome to estimate and control residual confounding effects of alcohol use and application of the intention-to-treat principle could provide a more realistic estimation of the true effects of alcohol use on health outcomes in observational epidemiological studies.