16 October 2015 In General Health

BACKGROUND: The association between Parkinson's disease and lifestyle exposures such as smoking, coffee and alcohol consumption have been the focus of research for several decades, with varying and often conflicting results.

OBJECTIVE: This paper reviews the key features of observational studies investigating the relationship between alcohol drinking and PD risk, to determine potential sources of variability between the results.

METHODS: Relevant literature from 2000-2014 was systematically retrieved using three databases. Primary research articles were included if they reported a measure of association between quantity and frequency of alcohol intake and PD risk, and adjusted at least for the potential confounding factors of smoking and age.

RESULTS: Sixteen articles were identified. The seven case-control studies were more likely to report a weak protective association by level of alcohol consumption compared to the studies with prospective designs. Two studies reported the relationship between heavy (harmful to health) drinking and PD. There was weak evidence that associations varied by type of alcoholic beverage. Smoking may modify the association between alcohol intake and PD risk, however, the evidence does not support the theory that a confounder (such as an addiction-avoiding personality trait) produced the inverse associations between smoking, coffee and alcohol intake and PD risk. Methodological weaknesses of the studies, including selection and recall bias, residual confounding and lack of statistical power may in part account for their differences.

CONCLUSION: The weak association between alcohol drinking and PD risk was found in studies at greater risk of selection and recall bias.

16 October 2015 In Cancer

AIMS: Cancers of female breast, upper aero-digestive tract (UADT) (oral cavity, pharynx, larynx, oesophagus) and colorectum are causally related to alcohol consumption. Although alcohol consumption is likely to vary during life, the few studies that have explicitly measured lifetime consumption or intake over time have not been summarised. We therefore conducted a systematic review and meta-analysis.

METHODS: Studies were identified by searching the Medline, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and Scopus databases through January 2015 using broad search criteria. Studies reporting relative risks (RR) for quantitatively defined categories of alcohol consumption over time for breast, UADT or colorectal cancer were eligible. A two-stage random-effects meta-analysis was used to estimate a dose-response relationship between alcohol intake and each cancer site. RRs were also calculated for the highest relative to the lowest intake category.

RESULTS: Sixteen articles for breast, 16 for UADT and 7 for colorectal cancer met the eligibility criteria. We observed a weak non-linear dose-response relationship for breast cancer and positive linear dose-response relationships for UADT and colorectal cancer. The pooled RRs were 1.28 (95% confidence interval, CI: 1.07, 1.52) for breast, 2.83 (95% CI: 1.73, 4.62) for UADT, 4.84 (95% CI: 2.51, 9.32) for oral cavity and pharynx, 2.25 (95% CI: 1.49, 3.42) for larynx, 6.71 (95% CI: 4.21, 10.70) for oesophageal and 1.49 (95% CI: 1.27, 1.74) for colorectal cancer.

CONCLUSION: Our findings confirm dose-dependent associations between long-term alcohol intake and breast, UADT and colorectal cancer.

16 October 2015 In Cancer

BACKGROUND: Breast cancer aetiology may differ by estrogen receptor (ER) status. Associations of alcohol and folate intakes with risk of breast cancer defined by ER status were examined in pooled analyses of the primary data from 20 cohorts.

METHODS: During a maximum of 6-18 years of follow-up of 1 089 273 women, 21 624 ER+ and 5113 ER- breast cancers were identified. Study-specific multivariable relative risks (RRs) were calculated using Cox proportional hazards regression models and then combined using a random-effects model.

RESULTS: Alcohol consumption was positively associated with risk of ER+ and ER- breast cancer. The pooled multivariable RRs (95% confidence intervals) comparing >/= 30 g/d with 0 g/day of alcohol consumption were 1.35 (1.23-1.48) for ER+ and 1.28 (1.10-1.49) for ER- breast cancer (Ptrend /= 0.26). Dietary (from foods only) and total folate intakes were not associated with risk of overall, ER+ and ER- breast cancer; pooled multivariable RRs ranged from 0.98 to 1.02 comparing extreme quintiles. Following-up US studies through only the period before mandatory folic acid fortification did not change the results. The alcohol and folate associations did not vary by tumour subtypes defined by progesterone receptor status.

CONCLUSIONS: Alcohol consumption was positively associated with risk of both ER+ and ER- breast cancer, even among women with high folate intake. Folate intake was not associated with breast cancer risk.

16 October 2015 In Cancer

OBJECTIVE: To estimate the proportion and numbers of cancers occurring in Australia in 2010 that are attributable to alcohol consumption.

METHODS: We estimated the population attributable fraction (PAF) of cancers causally associated with alcohol consumption using standard formulae incorporating prevalence of alcohol consumption and relative risks associated with consumption and cancer. We also estimated the proportion change in cancer incidence (potential impact fraction [PIF]) that might have occurred under the hypothetical scenario that an intervention reduced alcohol consumption, so that no-one drank >2 drinks/day.

RESULTS: An estimated 3,208 cancers (2.8% of all cancers) occurring in Australian adults in 2010 could be attributed to alcohol consumption. The greatest numbers were for cancers of the colon (868) and female breast cancer (830). The highest PAFs were for squamous cell carcinomas of the oral cavity/pharynx (31%) and oesophagus (25%). The incidence of alcohol-associated cancer types could have been reduced by 1,442 cases (4.3%) - from 33,537 to 32,083 - if no Australian adult consumed >2 drinks/day.

CONCLUSIONS: More than 3,000 cancers were attributable to alcohol consumption and thus were potentially preventable.

IMPLICATIONS: Strategies that limit alcohol consumption to guideline levels could prevent a large number of cancers in Australian adults.

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