to seven "standard" drinks per week, equivalent to 100 grams of pure alcohol per week. The other concluded that there is no safe level of alcohol, that "the level of consumption that minimises health loss is zero" and emphasized the need to revise alcohol control policies worldwide in order to reduce overall alcohol consumption. Alcohol-related death Over-consumption of alcohol causes many deaths worldwide. The overall mortality from alcohol use was found to be similar to that of the effect of physical inactivity. A review in 2009 found that "the net effect of alcohol consumption on health is detrimental, with an estimated 3.8% of all global deaths and 4.6% of global disability-adjusted life-years attributable to alcohol." Extensive research of Western cultures has consistently shown increased survival associated with light to moderate alcohol consumption. A 23-year prospective study of 12,000 male British physicians aged 48–78, found that overall mortality was significantly lower in current drinkers compared to non-drinkers even after correction for ex-drinkers. This benefit was strongest for ischemic heart disease, but was also noted for other vascular disease and respiratory disease. Death rate amongst current drinkers was higher for 'alcohol augmentable' disease such as liver disease and oral cancers, but these deaths were much less common than cardiovascular and respiratory deaths. The lowest mortality rate was found for consumption of 8 to 14 'units' per week. In the UK a unit is defined as 10ml or 8g of pure alcohol. Higher consumption increased overall mortality rate, but not above that of non-drinkers. Other studies have found age-dependent mortality risks of low-to-moderate alcohol use: an increased risk for individuals aged 16–34 (due to increased risk of cancers, accidents, liver disease, and other factors), but a decreased risk for individuals ages 55+ (due to lower incidence of ischemic heart disease). This is consistent with other research that found a J-curve dependency between alcohol consumption and total mortality among middle aged and older men. While the mortality rates of ex-drinkers and heavy drinkers are significantly elevated, the all-cause mortality rates may be 15–18% lower among moderate drinkers. Although the definition of a drink varies between studies and countries, this meta-analysis found that low levels of alcohol intake, defined as 1–2 drinks per day for women and 2–4 drinks per day for men, was associated with lower mortality than abstainers. This claim was challenged by another study that found that in certain low quality studies