Women's reproductive health factors and body adiposity: findings from the UK Biobank.

OBJECTIVE: To conduct a comprehensive examination of the association between women's reproductive health factors and measures of body adiposity in a contemporary Western population. METHODS: A cross-sectional analysis of 502 664 individuals from the UK Biobank was conducted. Multivariable linear regression models were used to examine the association of age at menarche, age at first birth, parity and age at menopause with measures of general and central body adiposity, adjusted for age, smoking and socioeconomic status. The association between number of children and body adiposity in men was also assessed. RESULTS: Age at menarche was inversely associated with body mass index (BMI); adjusted mean BMI was 29.0 kg m(-2) in women with menarche before the age of 12 years, compared with 26.5 kg m(-2) in those who had menarche after 14 years of age. Age at first birth was linearly and inversely associated with BMI: 0.16 kg m(-2) lower BMI per year increase in age of first birth. Each additional live birth or child fathered was associated with a 0.22 kg m(-2) higher BMI in women and a 0.14 kg m(-2) higher BMI in men. There was no evidence for an association between age at menopause and BMI. Corresponding associations for other markers of general or abdominal adiposity were similar to those for BMI. Findings were broadly similar in analyses stratified by age, smoking status, socioeconomic status, ethnic background, and history of diabetes or cardiovascular disease. CONCLUSIONS: In women from a contemporary Western population, earlier age at menarche and age at first birth, and higher number of total live births were associated with higher levels of body adiposity. Prospective evaluations of the association between reproductive health factors, adiposity and the onset of cardiometabolic diseases are needed to assess causality, and to explore the mechanisms involved.

Effects of blood pressure lowering on cardiovascular risk according to baseline body-mass index: a meta-analysis of randomised trials.

BACKGROUND: The cardiovascular benefits of blood pressure lowering in obese people compared with people of normal weight might depend on choice of drug. We compared the effects of blood pressure-lowering regimens on cardiovascular risk in groups of patients categorised by baseline body-mass index (BMI). METHODS: We used individual patient data from trials included in the Blood Pressure Lowering Treatment Trialists' Collaboration to compare the effects of different classes of blood pressure-lowering regimens for the primary outcome of total major cardiovascular events (stroke, coronary heart disease, heart failure, and cardiovascular death). We used meta-analyses and meta-regressions to assess interactions between treatment and BMI when fitted as either a categorical variable (<25 kg/m(2), 25 to <30 kg/m(2), and ≥30 kg/m(2)) or a continuous variable. FINDINGS: Analyses were based on 135,715 individuals from 22 trials who had 14,353 major cardiovascular events. None of the six primary comparisons showed evidence that protection varied by drug class across the three BMI groups (all p for trend >0·20). When analysed as a continuous variable, angiotensin-converting-enzyme inhibitors gave slightly greater protection for each 5 kg/m(2) higher BMI than did calcium antagonists (hazard ratio 0·93, 95% CI 0·89-0·98; p=0·004) or diuretics (0·93, 0·89-0·98; p=0·002). The meta-regressions showed no relation between BMI category and the risk reduction for a given fall in systolic blood pressure. By contrast with a previous report, we noted no relation between BMI and the efficacy of calcium antagonists compared with diuretics. INTERPRETATION: We found little evidence that selection of a particular class of blood pressure-lowering drug will lead to substantially different outcomes for individuals who are obese compared with those who are lean. FUNDING: None.

Oral disease in relation to future risk of dementia and cognitive decline: prospective cohort study based on the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified-Release Controlled Evaluation (ADVANCE) trial.

OBJECTIVE: Examine the association of oral disease with future dementia/cognitive decline in a cohort of people with type 2 diabetes. METHODS: A total of 11,140 men and women aged 55-88 years at study induction with type 2 diabetes participated in a baseline medical examination when they reported the number of natural teeth and days of bleeding gums. Dementia and cognitive decline were ascertained periodically during a 5-year follow-up. RESULTS: Relative to the group with the greatest number of teeth (more than or equal to 22), having no teeth was associated with the highest risk of both dementia (hazard ratio; 95% confidence interval: 1.48; 1.24, 1.78) and cognitive decline (1.39; 1.21, 1.59). Number of days of bleeding gums was unrelated to these outcomes. CONCLUSIONS: Tooth loss was associated with an increased risk of both dementia and cognitive decline.

Age at menarche and risk of type 2 diabetes among African-American and white women in the Atherosclerosis Risk in Communities (ARIC) study.

AIMS/HYPOTHESIS: We examined race differences in the association between age at menarche and type 2 diabetes before and after adjustment for adiposity. METHODS: We analysed baseline and 9-year follow-up data from 8,491 women (n = 2,505 African-American, mean age 53.3 years; n = 5,986 white, mean age 54.0 years) in the Atherosclerosis Risk in Communities (ARIC) study. Stratifying by race, we used logistic regression to estimate the OR for prevalent diabetes at baseline, and Cox proportional hazard models to estimate the HR for incident diabetes over follow-up according to age at menarche category (8-11, 12, 13, 14 and 15-18 years). RESULTS: Adjusting for age and centre, we found that early age at menarche (8-11 vs 13 years) was associated with diabetes for white, but not African-American women in both the prevalent (white OR 1.72, 95% CI 1.32, 2.25; African-American OR 1.13, 95% CI 0.84, 1.51; interaction p = 0.043) and incident models (white HR 1.43, 95% CI 1.08, 1.89; African-American HR 1.20, 95% CI 0.87, 1.67; interaction p = 0.527). Adjustment for adiposity and lifestyle confounders attenuated associations for prevalent (white OR 1.41, 95% CI 1.05, 1.89; African-American OR 0.94, 95% CI 0.68, 1.30; interaction p = 0.093) and incident diabetes (white HR 1.22, 95% CI 0.92, 1.63; African-American HR 1.11, 95% CI 0.80, 1.56; interaction p = 0.554). CONCLUSIONS/INTERPRETATION: Early menarche was associated with type 2 diabetes in white women, and adulthood adiposity attenuated the relationship. We did not find a similar association in African-American women. Our findings suggest that there may be race/ethnic differences in the influence of developmental factors in the aetiology of type 2 diabetes, which merit further investigation.

Associations of diabetes mellitus with site-specific cancer mortality in the Asia-Pacific region.

BACKGROUND: Owing to the increasing prevalence of obesity and diabetes in Asia, and the paucity of studies, we examined the influence of raised blood glucose and diabetes on cancer mortality risk. MATERIALS AND METHODS: Thirty-six cohort Asian and Australasian studies provided 367, 361 participants (74% from Asia); 6% had diabetes at baseline. Associations between diabetes and site-specific cancer mortality were estimated using time-dependent Cox models, stratified by study and sex, and adjusted for age. RESULTS: During a median follow-up of 4.0 years, there were 5992 deaths due to cancer (74% Asian; 41% female). Participants with diabetes had 23% greater risk of mortality from all-cause cancer compared with those without: hazard ratio (HR) 1.23 [95% confidence interval (CI) 1.12, 1.35]. Diabetes was associated with mortality due to cancer of the liver (HR 1.51; 95% CI 1.19, 1.91), pancreas (HR 1.78; 95% CI 1.20, 2.65), and, less strongly, colorectum (HR 1.32; 95% CI 0.98, 1.78). There was no evidence of sex- or region-specific differences in these associations. The population attributable fractions for cancer mortality due to diabetes were generally higher for Asia compared with non-Asian populations. CONCLUSION: Diabetes is associated with increased mortality from selected cancers in Asian and non-Asian populations.

Associations between gender, age and waist circumference.

In December 2008, the World Health Organization (WHO) convened a consultation to discuss cut-points for waist circumference (WC). As part of that effort, this paper examines the impact of gender and age on WC. As WC is influenced by body weight, body composition and fat distribution, their associations with gender and age were reviewed. We also noted the relationships with sex hormones, parity and menopause. We then summarized data on gender, age and WC. This presentation is not intended to be comprehensive, but to provide an overview of the available research. There are large differences in body composition in men and women, with women having more body fat. Fat distribution also differs with gender, with men having a relatively more central distribution of fat. These differences begin early in life and become more apparent in puberty due to changes in sex hormone levels. In both, men and women, waist and waist-to-hip ratio increase with age. A large portion of this increase is driven by gains in body weight, but the increases observed are larger than those that would be predicted from increases in the body mass index alone, and increases in WC are seen with aging in the absence of weight gain. The current practice of using seperate waist cut-points by gender is appropriate. Although WC increases with age, so does the risk of many chronic diseases. An evaluation of the need for age-specific waist cut-points in adults would need to consider disease risk.

The discrimination of dyslipidaemia using anthropometric measures in ethnically diverse populations of the Asia-Pacific Region: the Obesity in Asia Collaboration.

Dyslipidaemia is a major risk factor for cardiovascular disease and is only detectable through blood testing, which may not be feasible in resource-poor settings. As dyslipidaemia is commonly associated with excess weight, it may be possible to identify individuals with adverse lipid profiles using simple anthropometric measures. A total of 222 975 individuals from 18 studies were included as part of the Obesity in Asia Collaboration. Linear and logistic regression models were used to assess the association between measures of body size and dyslipidaemia. Body mass index, waist circumference, waist : hip ratio (WHR) and waist : height ratio were continuously associated with the lipid variables studied, but the relationships were consistently stronger for triglycerides and high-density lipoprotein cholesterol. The associations were similar between Asians and non-Asians, and no single anthropometric measure was superior at discriminating those individuals at increased risk of dyslipidaemia. WHR cut-points of 0.8 in women and 0.9 in men were applicable across both Asians and non-Asians for the discrimination of individuals with any form of dyslipidaemia. Measurement of central obesity may help to identify those individuals at increased risk of dyslipidaemia. WHR cut-points of 0.8 for women and 0.9 for men are optimal for discriminating those individuals likely to have adverse lipid profiles and in need of further clinical assessment.

Body mass index, waist circumference and waist:hip ratio as predictors of cardiovascular risk--a review of the literature.

Overweight and obesity have become a major public health problem in both developing and developed countries as they are causally related to a wide spectrum of chronic diseases including type II diabetes, cardiovascular diseases and cancer. However, uncertainty regarding the most appropriate means by which to define excess body weight remains. Traditionally, body mass index (BMI) has been the most widely used method by which to determine the prevalence of overweight in, and across, populations as well as an individual's level of risk. However, in recent years, measures of central obesity, principally waist circumference and the waist:hip ratio and to a lesser extent the waist:height ratio, which more accurately describe the distribution of body fat compared with BMI, have been suggested to be more closely associated with subsequent morbidity and mortality. There is also uncertainty about how these measures perform across diverse ethnic groups; earlier, most of the evidence regarding the relationships between excess weight and risk has been derived chiefly from Caucasian populations, and hence, it remains unclear whether the relationships are consistent in non-Caucasian populations. The purpose of this review, therefore, is to provide an overview of the current evidence-base focusing predominantly on three main questions: (1) Which, if any, of the commonly used anthropometric measures to define excess weight is more strongly associated with cardiovascular risk? (2) Which of the anthropometric measures is a better discriminator of risk? and (3) Are there any notable differences in the strength and nature of these associations across diverse ethnic groups?

Adult height and cancer mortality in Asia: the Asia Pacific Cohort Studies Collaboration.

BACKGROUND: The observation that taller people experience an increased risk of selected cancers is largely restricted to Caucasian cohorts. These associations may plausibly differ in Asian populations. For the first time, we make direct comparison in the same analyses of the associations between height and a series of malignancies in Australasian (Caucasian) and Asian populations. METHODS: Analyses were based on the Asia Pacific Cohort Studies Collaboration of 506 648 study participants (408 381 Asia, 98 267 Australasia) drawn from 38 population-based cohort studies. Cox proportional hazards regression was used to estimate the relationship between height and cancer rates. RESULTS: A total of 3 272 600 person-years of follow-up gave rise to 7497 cancer deaths (4415 in Asia; 3082 in Australasia). After multiple adjustments and left censoring, taller individuals experienced increased rates of carcinoma of the intestine (men and women); all cancers, liver, lung, breast, 'other' malignancies (all women); and cancers of the prostate and bladder (men). No consistent regional (Asia versus Australasia) or sex differences were observed. CONCLUSIONS: In the present study, taller men and women had an elevated risk of selected malignancies. These associations did not differ appreciably between Asian and Caucasian populations.

Efficacy of weight loss drugs on obesity and cardiovascular risk factors in obese adolescents: a meta-analysis of randomized controlled trials.

Weight loss drugs have been developed to reduce the comorbidities associated with excess weight. We conducted a meta-analysis of the efficacy of orlistat and sibutramine on weight, body mass index, waist circumference and cardiovascular risk factors in overweight adolescents. MEDLINE and the Cochrane Library were searched for relevant articles using MESH terms and keywords. Studies were included if they had reported quantitative estimates and standard deviations of the association between each weight loss drug and weight, with information on at least one cardiovascular risk factor. A total of eight trials (three orlistat and five sibutramine) with information on 1391 individuals was included in the present analysis. The mean decrease in weight between the intervention and control groups was 5.25 kg (95% confidence interval: 3.03-7.48) after a minimum follow-up of 6 months. There was evidence of statistical heterogeneity between the studies (I(2) = 76%) that was no longer apparent after exclusion of trials of orlistat (mean weight decrease = 5.32 kg; I(2) = 38%). There was little evidence that treatment was associated with adverse effects on cardiovascular risk factors but this requires verification from future large trials with longer study follow-up.

The hazards and benefits associated with smoking and smoking cessation in Asia: a meta-analysis of prospective studies.

OBJECTIVE: To provide the most reliable evidence as to the nature of the associations between smoking and cause-specific illness, as well as the expected benefits from quitting smoking, in studies conducted in Asia, where smoking remains popular among men. DATA SOURCES: Studies published between January 1966 and October 2008, identified in the Medline search strategy with medical subject headings, in addition to studies from the Asia Pacific Cohort Studies Collaboration. STUDY SELECTION: Studies were considered to be relevant if they were prospective studies, in an Asian setting that reported on the association between smoking, quitting and cause-specific illness. DATA EXTRACTION: Two reviewers independently screened all identified articles for possible inclusion and extracted data. DATA SYNTHESIS: The pooled relative risks (RRs) for incidence or mortality, comparing current to never smokers were always significantly higher than unity; the highest was for lung cancer: 3.54 (95% confidence interval 3.00 to 4.17). The pooled RRs for former smokers (compared to never smokers) were also always significantly higher than unity, and were lower than in current smokers, for coronary heart disease, stroke, lung and upper aero-digestive tract cancer. Only for respiratory disease was the RR for former smokers higher than that for current smokers. CONCLUSIONS: This meta-analysis has shown that, despite the relative immaturity of the smoking epidemic in Asia, smoking is unquestionably a major contributor to ill health and death. However, the beneficial effects of quitting are not yet always apparent, most probably because quitting is a consequence of ill health and the relative unpopularity of smoking cessation in many Asian populations.

Does cigarette smoking exacerbate the effect of total cholesterol and high-density lipoprotein cholesterol on the risk of cardiovascular diseases?

OBJECTIVE: To explore whether an interaction between smoking and serum total cholesterol (TC) and/or decreased levels of serum high-density lipoprotein cholesterol (HDLC) exists for any major subtype of cardiovascular disease. DESIGN: An individual participant overview of 34 cohort studies. SETTING: The Asia-Pacific region. PARTICIPANTS: People aged >or=20 years without a particular condition or risk factor. MEAN OUTCOME MEASURES: Hazard ratios (HRs) and 95% confidence intervals (CIs) for both TC and HDLC by smoking status were estimated using Cox proportional hazard models adjusted for age and systolic blood pressure and stratified by study and sex. RESULTS: During follow-up (median 4.0 years), 3298 coronary heart disease (CHD) and 4318 stroke events were recorded. For CHD, the HR (95% CI) for an additional 1.06 mmol/l increment in TC was greater in current smokers than in non-smokers: 1.54 (1.43 to 1.66) versus 1.38 (1.30 to 1.47); p = 0.02. Similarly, the HR (95% CI) for an additional 0.40 mmol/l decrement in HDLC was greater in current smokers than in non-smokers: 1.67 (1.35 to 2.07) versus 1.28 (1.10 to 1.49); p = 0.04. The positive association of TC with ischaemic stroke, and the negative association of TC with haemorrhagic stroke, were broadly similar for current smokers and non-smokers. Similarly, the risks of both the subtypes of stroke remained broadly unchanged as HDLC decreased in both current smokers and non-smokers. CONCLUSIONS: Smoking exacerbated the effects of both TC and HDLC on CHD, although no interaction between smoking and TC or HDLC existed for either of the subtypes of stroke.

Obesity and overweight in relation to liver disease mortality in men: 38 year follow-up of the original Whitehall study.

Obesity has been implicated in the aetiology of liver disease. However, to date, evidence is largely drawn from cross-sectional studies, where interpretation is hampered by reverse causality, and from studies on clinical populations that have limited generalisability. In this prospective cohort study, data on body mass index (BMI) and covariates were collected at baseline on 18 863 male government employees (aged 40-69 years). Respondents were then followed up for a maximum of 38 years of age. Mortality surveillance gave rise to 13 129 deaths, 122 of which were due to liver disease (57 cancers; 65 non-cancers). In age-adjusted analyses, BMI was positively related to total liver disease mortality (hazards ratio per 1 s.d. increase in BMI; 95% confidence interval (CI): 1.36; 1.14, 1.62) in a graded fashion across the weight categories (P-value for trend: 0.01). The magnitude of this association was somewhat stronger for non-cancer liver disease deaths (1.47; 1.16, 1.86) than for cancer liver disease deaths (1.25; 0.96, 1.62). Excluding deaths in the first 10 years of follow-up somewhat strengthened the BMI-non-cancer liver disease association. Adjustment for socioeconomic position, other candidate confounders and mediating factors led to the modest attenuation of these associations. Further investigation in prospective cohort studies with more detailed data on liver disease, for instance using biochemical tests of liver function or hepatic ultrasonography, is warranted.

Association of smoking and smoking cessation with major causes of mortality in the Asia Pacific Region: the Asia Pacific Cohort Studies Collaboration.

BACKGROUND: Although the dangers of smoking, and the benefits of quitting, are well established and understood in the West, smoking remains popular among Asian men. We investigated the associations between smoking (including ex-smoking) and major causes of mortality in Asian men and women, and compared with Australians and New Zealanders (ANZ). METHODS: An overview of 34 cohort studies in the Asia Pacific region involving 512 676 individuals (81% from Asia), followed up for a median of 6.7 years (20 804 deaths). RESULTS: Mortality rates for cause-specific and all causes of mortality were systematically higher for current compared with never smokers. Hazard ratios (HR) for overall and cause-specific mortality comparing current-smokers with never smokers, ex- smokers with current-smokers and comparing numbers of cigarettes smoked per day, were higher for ANZ than Asia (p<0.001). For overall mortality, the HR (95% CI) comparing current-smoking with not was 1.37 (1.23 to 1.53) and 1.33 (1.26 to 1.40) in Asian men and women respectively. The corresponding figures in ANZ were 1.95 (1.81 to 2.09) and 1.85 (1.69 to 2.02). The HR for quitting in ANZ was 0.67 (0.63 to 0.71) and 0.66 (0.58 to 0.74) in men and women respectively. Quitting smoking had a significant benefit among Asian men, the HR was 0.88 (0.81 to 0.97) after ignoring the first 3 years of follow-up. There was no evidence of benefit for Asian women, for whom ex-smoking is rare. CONCLUSIONS: Allowing for the recent uptake of smoking in Asia, its effects are comparable to those observed in ANZ. Stringent tobacco control measures and smoking cessation strategies are urgently required in Asia.

A systematic review of school-based intervention studies for the prevention or reduction of excess weight among Chinese children and adolescents.

The aim of this paper was to conduct a systematic review of intervention studies in China aimed at the prevention or control of excess weight gain among children and adolescents. Two Chinese databases (The China Full Text Database and Wanfang Database) and two English databases (Medline and Meditext) were searched with keywords for intervention studies published between 1990 and 2006. Data were extracted on aspects of study quality, methodology and effectiveness of interventions. Quality assessment was conducted using a previously established assessment tool. Twenty-two studies were included, of which 17 were conducted among overweight and/or obese children and/or adolescents. Interventions strategies varied across studies but the majority focused on improving the level of knowledge, physical activity levels and/or diet of overweight children and adolescents. Most studies reported a beneficial effect of the intervention with one or more of the study outcomes, but all of the studies had serious, or moderate, methodological weaknesses. None of the trials identified by this systematic review demonstrated convincing evidence of the efficacy of any single intervention for the prevention of overweight and obesity in children and adolescents from Mainland China. Future intervention trials should address the methodological weaknesses identified in this review.

Ethnic comparisons of the cross-sectional relationships between measures of body size with diabetes and hypertension.

Recent estimates indicate that two billion people are overweight or obese and hence are at increased risk of cardiovascular disease and its comorbidities. However, this may be an underestimate of the true extent of the problem, as the current method used to define overweight may lack sensitivity, particularly in some ethnic groups where there may be an underestimate of risk. Measures of central obesity may be more strongly associated with cardiovascular risk, but there has been no systematic attempt to compare the strength and nature of the associations between different measures of overweight with cardiovascular risk across ethnic groups. Data from the Obesity in Asia Collaboration, comprising 21 cross-sectional studies in the Asia-Pacific region with information on more than 263,000 individuals, indicate that measures of central obesity, in particular, waist circumference (WC), are better discriminators of prevalent diabetes and hypertension in Asians and Caucasians, and are more strongly associated with prevalent diabetes (but not hypertension), compared with body mass index (BMI). For any given level of BMI, WC or waist:hip ratio, the absolute risk of diabetes or hypertension tended to be higher among Asians compared with Caucasians, supporting the use of lower anthropometric cut-points to indicate overweight among Asians.

Leisure-time physical activity alone may not be a sufficient public health approach to prevent obesity--a focus on China.

Much small-scale research has identified the role of physical activity in obesity prevention. This is the 'energy expenditure' side of the energy balance equation. Although around half an hour of daily moderate-intensity physical activity is required for cardiovascular health and disease prevention, the quantum of physical activity required for obesity prevention and weight loss is around 60-90 minutes per day. This amount of physical activity is difficult to achieve through leisure time physical activity (LTPA) alone, and additional energy expenditure is needed in the domains of active transport, occupation activity and in domestic settings. Modeling of 24-hour energy expenditures demonstrate the need for 'active living', namely energy expenditure over and above that due to LTPA, for weight loss and obesity prevention. The consequences of this for developing countries such as China are the need to focus on preventing the declines in energy expenditure attributable to urbanization, industrialization, and motor vehicle dependence. These will pose policy challenges in the developing world, if they are to be taken seriously as obesity prevention strategies.

The role of lifestyle risk factors on mortality from colorectal cancer in populations of the Asia-Pacific region.

Although colorectal cancer is one of the leading malignancies worldwide, there are few data on aetiological relationships from the Asia-Pacific region. Therefore, a collaborative study was conducted involving over half a million subjects from 33 cohort studies in the region. Age-adjusted death rates from colorectal cancer, over an average of 6.8 years follow-up, were 12 and 14 per 100,000 person-years among Asian women and men, respectively; corresponding values in Australasia were 31 and 41. Height was strongly associated with death from colorectal cancer: an extra 5 cm of height was associated with 10% (95%confidence interval, 3% - 18% additional risk, after adjustment for other factors. Smoking increased risk by 43% (9% - 88%), although no significant dose-response relationship was discerned (p>0.05). Other significant (p <0.05) risk factors were body mass index and lack of physical activity. There was no significant effect on colorectal cancer mortality for alcohol consumption, waist circumference, fasting blood glucose or diabetes, although the latter conferred a notable 26% additional risk. Height may be a biomarker for some currently unknown genetic, or environmental, risk factors that are related both to skeletal growth and mutanogenesis. Understanding such mechanisms could provide opportunities for novel preventive and therapeutic intervention.

The impact of modifiable risk factors on mortality from prostate cancer in populations of the Asia-Pacific region.

Mortality from cancer of the prostate is increasing in the Asia-Pacific, when much of this region is undergoing a transition to a Western lifestyle. The role that lifestyle factors play in prostate cancer appears limited, but existing data mainly are from the West. We conducted an individual participant data analysis of 24 cohort studies involving 320,852 men (83% in Asia). Cox proportional hazard models were used to quantify associations between risk factors and mortality from prostate cancer. There were 308 deaths from prostate cancer (14% in Asia) during 2.1 million person-years of follow-up. The age-adjusted hazard ratio (95% confidence interval; CI) for men with body mass index (BMI) 28 kg/m2 or more, compared with below 25, was 1.55 (1.12 - 2.16); no such significant relationship was found for height or waist circumference. The BMI result was unchanged after adjustment for other variables, was consistent between Asia and Australia/New Zealand (ANZ) and did not differ with age. There was no significant relationship with diabetes, glucose or total cholesterol (p > or = 0.18). Smoking, alone, showed different effects in the two regions, possibly due to the relative immaturity of the smoking epidemic in Asia. In ANZ, the multiple-adjusted hazard ratio for an extra 5 cigarettes per day was 1.12 (95%CI: 1.03 - 1.22), whereas in Asia it was 0.77 (0.56 - 1.05). Body size is an apparently important determinant of prostate cancer in the Asia-Pacific. Evidence of an adverse effect of smoking is conclusive only in the predominantly Caucasian parts of the region.

Impact of smoking and smoking cessation on lung cancer mortality in the Asia-Pacific region.

Cigarette smoking is becoming increasingly common in Asia while quitting remains rare, in part because of a lack of knowledge about the risks of smoking. This study compared the risk of death from lung cancer associated with smoking habits in Australia and New Zealand and in Asia by using data from the Asia Pacific Cohort Studies Collaboration: 31 studies involving 480,125 individuals. Cox regression models were used. The hazard ratios for lung cancer mortality associated with current smoking were, for men, 2.48 (95% confidence interval (CI): 1.99, 3.11) in Asia versus 9.87 (95% CI: 6.04, 16.12) in Australia and New Zealand; p for homogeneity <0.0001. For women, the corresponding estimates were 2.35 (95% CI: 1.29, 4.28) in Asia versus 19.33 (95% CI: 10.0, 37.3) in Australia and New Zealand; p for homogeneity <0.0001. Quitting was beneficial in both regions; the hazard ratios for former compared with current smokers were 0.69 (95% CI: 0.53, 0.92) in Asia and 0.30 (95% CI: 0.22, 0.41) in Australia and New Zealand. The lesser effect in Asia was partly explained by the fewer number of cigarettes smoked and the shorter duration of follow-up in Asian studies. These results suggest that tobacco control policies in Asia should not solely concentrate on preventing the uptake of smoking but also attend to cessation.