Jillian Boreham’s research while affiliated with University of Oxford and other places

This book analyses patterns in rural China in the late 1980s: patterns of causes of death, of what people ate, what they smoked and drank, what kinds of houses they lived in, what they worked at, their education, and many measurements of their blood (for cholesterol, vitamins, evidence of infectious disease) and urine (for food metabolites and other factors). The variation is examined at the level of counties scattered all over mainland China and Taiwan, representing the extremes of values for deaths from specific cancers; ie the counties with the highest and the lowest rates of lung cancer, or the highest and lowest for liver cancer. Coincidentally, this covers the extremes of many of the other variables, such as the intake of fresh fruits and vegetables, and smoking rates. The analysis that fills the pages is the correlation of all of these patterns, one variable at a time, with all the others. The question it answers is, “How well does the variation among the counties for one variable (eg cholesterol in the blood) correlate with the variation across China in deaths from different diseases (eg heart disease)?”. If the correlation is strong, it may mean that the variables are related in some causal sense, although this cannot be assumed. If the correlation is weak, it means that the variation must be caused mainly by other factors. Importantly, if the correlation is weak, it does not necessarily mean that the two variables are not related; for example, a weak correlation between blood cholesterol and deaths from heart disease does not mean that cholesterol is not implicated in heart disease, but that in China other factors are more important. Each variable page is similarly arranged, and there are keys to interpreting each element at the beginning of major sections. The book also includes numerous extra tables in the back that give mean values for many variables. These can be useful as many of these values in China are so different from the much more available and common Western values. We tend to think of the range of Western variables as somehow normal , without realizing that in China the mean value may not even be within the generally accepted normal range that we are used to.

Russian adults have extraordinarily high rates of premature death. Retrospective enquiries to the families of about 50 000 deceased Russians had found excess vodka use among those dying from external causes (accident, suicide, violence) and eight particular disease groupings. We now seek prospective evidence of these associations. In three Russian cities (Barnaul, Byisk, and Tomsk), we interviewed 200 000 adults during 1999-2008 (with 12 000 re-interviewed some years later) and followed them until 2010 for cause-specific mortality. In 151 000 with no previous disease and some follow-up at ages 35-74 years, Poisson regression (adjusted for age at risk, amount smoked, education, and city) was used to calculate the relative risks associating vodka consumption with mortality. We have combined these relative risks with age-specific death rates to get 20-year absolute risks. Among 57 361 male smokers with no previous disease, the estimated 20-year risks of death at ages 35-54 years were 16% (95% CI 15-17) for those who reported consuming less than a bottle of vodka per week at baseline, 20% (18-22) for those consuming 1-2·9 bottles per week, and 35% (31-39) for those consuming three or more bottles per week; trend p<0·0001. The corresponding risks of death at ages 55-74 years were 50% (48-52) for those who reported consuming less than a bottle of vodka per week at baseline, 54% (51-57) for those consuming 1-2·9 bottles per week, and 64% (59-69) for those consuming three or more bottles per week; trend p<0·0001. In both age ranges most of the excess mortality in heavier drinkers was from external causes or the eight disease groupings strongly associated with alcohol in the retrospective enquiries. Self-reported drinking fluctuated; of the men who reported drinking three or more bottles of vodka per week who were reinterviewed a few years later, about half (185 of 321) then reported drinking less than one bottle per week. Such fluctuations must have substantially attenuated the apparent hazards of heavy drinking in this study, yet self-reported vodka use at baseline still strongly predicted risk. Among male non-smokers and among females, self-reported heavy drinking was uncommon, but seemed to involve similar absolute excess risks. This large prospective study strongly reinforces other evidence that vodka is a major cause of the high risk of premature death in Russian adults. UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Union, WHO International Agency for Research on Cancer.

A four-stage model of the cigarette epidemic was proposed in 1994 to communicate the long delay between the widespread uptake of cigarette smoking and its full effects on mortality, as had been experienced in economically developed countries where cigarette smoking became entrenched decades earlier in men than in women. In the present work, the question of whether qualitative predictions from the model have matched recent trends in smoking and deaths from smoking in countries at various levels of economic development is assessed, and possible projections to the year 2025 are considered. The proportion of all deaths attributed to tobacco was estimated indirectly for 41 high-resource and medium-resource countries from 1950 to the most recent year for which data were available, generally about 2005-2009. The trends in tobacco-attributed mortality in later middle age were then projected forward to 2025, based on recent trends in tobacco-attributed mortality in early middle age. In developed countries the prevalence of smoking has continued to decrease in both sexes, although the rate of decrease has slowed and is less than that predicted by the original version of the model. Over the past 20 years the proportionate contribution of smoking to all deaths has decreased in men while continuing to increase or plateau among women. Although the proportion of all deaths at ages 35-69 that are attributed to smoking is still generally greater in men than in women, the male and female proportions are converging and will probably cross over in some high resource countries. Projections through to 2025 suggest that male and female smoking prevalence and smoking-attributed mortality will decrease in parallel in most developed countries towards lower limits that are not yet defined. In developing countries the model seems generally applicable to men but cannot predict whether or when women will begin smoking in large numbers. Modified criteria that describe the stages of the epidemic separately for men and women would be more generalisable to developing countries. The four-stage model of the cigarette epidemic still provides a reasonably useful description in many developed countries. Its relevance to developing countries could be improved by describing the stages of the epidemic separately for men and women.

Low body mass index (BMI) is associated with chronic obstructive pulmonary disease (COPD) in populations where many are overweight. Substantial uncertainty remains about the relationship in populations with lower mean BMI levels, and about the relevance to it of the effects of smoking or of reverse causality. A nationally representative prospective cohort study included 221,194 Chinese men aged 40-79 years in 1990-91, who were followed up for 15 years or to the age of 80 years. Hazard ratios for COPD-related mortality vs baseline BMI were adjusted for age, smoking, drinking and other factors. To reduce reverse causality, main analyses excluded all men with prior history of any respiratory diseases or abnormal lung function at baseline, leaving 2960 COPD-related deaths (16% of all deaths). The mean baseline BMI was 21.7 kg/m(2). There was a highly significant inverse association between BMI and COPD-related mortality among men without any apparent impairment of lung function. Approximately 90% of men had a baseline BMI <25 kg/m(2), and among them, 5 kg/m(2) lower BMI was associated with 31% (95% confidence interval 18-45%) higher COPD-related mortality. The excess risk persisted after restricting the analysis to never-smokers or excluding the first 5 years of follow-up. Low BMI is associated with increased COPD mortality in a relatively lean adult male population in China where COPD is one of the most common causes of death.

Low body mass index (BMI) has been associated with increased risk of lung cancer. However, the nature of the association, especially in populations with relatively low BMI, is less well characterized, as is the relevance to it of smoking. A nationally representative prospective cohort study included 217,180 Chinese men aged 40-79 years in 1990-91 who had no prior history of cancer and were followed up for 15 years. Standardized hazard ratios (HRs) were calculated for lung cancer mortality by baseline BMI. The mean baseline BMI was 21.7 kg/m(2), and 2,145 lung cancer deaths were recorded during 15 years of follow-up. The prevalence of smoking was strongly inversely associated with BMI, but no apparent relationship was seen between amount smoked (or other measures of smoking intensity) and BMI among smokers. Overall there was a strong inverse association between BMI and lung cancer mortality (p < 0.0001 for trend) after excluding the first 3 years of follow-up. This association appeared to be confined mainly to current smokers, with no apparent relationship in nonsmokers (p < 0.001 for difference between slopes). Among current smokers, the inverse association appeared to be log-linear, with each 5 kg/m(2) lower BMI associated with a 35% (95% confidence interval: 24-46%; p < 0.0001) higher lung cancer mortality, and it persisted after excluding those who had reported poor health status or history of any disease or respiratory symptoms at baseline. In this relatively lean Chinese male population, low BMI was strongly associated with increased risk of lung cancer only among current smokers.