National Drug Research Institute, Faculty of Health Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Kirby Institute, University of New South Wales, Level 6, Wallace Wurth Building, High Street, Kensington NSW 2052, Australia.
Int J Environ Res Public Health. 2020 Feb 19;17(4):1343. doi: 10.3390/ijerph17041343.
A national tax increase, which became known as the "alcopops tax", was introduced in Australia on the 27th April 2008 on ready-to-drink alcoholic beverages, which are consumed predominantly by young people. The affordability of alcohol has been identified as the strongest environmental driver of alcohol consumption, and alcohol consumption is a well-known risk factor in the spread of sexually transmitted infections via its association with sexual risk-taking. We conducted a study to investigate whether there was any association between the introduction of the tax and changes in national chlamydia rates: (i) notification rates (diagnoses per 100,000 population; primary outcome and standard approach in alcohol taxation studies), and (ii) test positivity rates (diagnoses per 100 tests; secondary outcome) among 15-24 and 25-34-year-olds, using interrupted time series analysis. Gender- and age-specific chlamydia trends among those 35 and older were applied as internal control series and gender- and age-specific consumer price index-adjusted per capita income trends were controlled for as independent variables. We hypothesised that the expected negative association between the tax and chlamydia notification rates might be masked due to increasing chlamydia test counts over the observation period (2000 to 2016). We hypothesised that the association between the tax and chlamydia test positivity rates would occur as an immediate level decrease, as a result of a decrease in alcohol consumption, which, in turn, would lead to a decrease in risky sexual behaviour and, hence, chlamydia transmission. None of the gender and age-specific population-based rates indicated a significant immediate or lagged association with the tax. However, we found an immediate decrease in test positivity rates for 25-34-year-old males (27% reduction-equivalent to 11,891 cases prevented post-tax) that remained detectable up to a lag of six months and a decrease at a lag of six months for 15-24-year-old males (31% reduction-equivalent to 16,615 cases prevented) following the tax. For no other gender or age combination did the change in test positivity rates reach significance. This study adds to the evidence base supporting the use of alcohol taxation to reduce health-related harms experienced by young people and offers a novel method for calculating sexually transmitted infection rates for policy evaluation.
一项全国性的增税措施，即所谓的“预调酒税”，于 2008 年 4 月 27 日在澳大利亚对即饮酒精饮料征收，这些饮料主要被年轻人消费。酒精的可负担性被认为是影响酒精消费的最强环境驱动因素，而酒精消费是性传播感染传播的一个众所周知的风险因素，因为它与性冒险行为有关。我们进行了一项研究，以调查税收的引入是否与全国衣原体率的变化有关：（i）通知率（每 10 万人的诊断数；作为酒精税收研究的主要结果和标准方法），以及（ii）15-24 岁和 25-34 岁人群中的检测阳性率（每 100 次检测的诊断数；次要结果），使用中断时间序列分析。35 岁及以上人群的性别和年龄特异性衣原体趋势被用作内部对照系列，并控制性别和年龄特异性消费价格指数调整后的人均收入趋势作为自变量。我们假设，由于观察期间（2000 年至 2016 年）衣原体检测数量的增加，税收与衣原体通知率之间预期的负相关可能会被掩盖。我们假设，由于酒精消费减少，税收与衣原体检测阳性率之间的关联将立即出现水平下降，这反过来又会导致性行为风险降低，从而降低衣原体传播。基于人群的性别和年龄特异性率均未显示与税收有显著的即时或滞后关联。然而，我们发现 25-34 岁男性的检测阳性率立即下降（27%的降幅，相当于税收后预防了 11891 例病例），在六个月的滞后期内仍可检测到，而 15-24 岁男性的检测阳性率在六个月的滞后期内下降（31%的降幅，相当于税收后预防了 16615 例病例）。对于其他任何性别或年龄组合，检测阳性率的变化均未达到显著水平。这项研究为支持使用酒精税收来减少年轻人所经历的与健康相关的危害提供了证据基础，并为政策评估提供了一种计算性传播感染率的新方法。
