Body mass index, smoking, and risk of death between 40 and 70 years of age in a Norwegian cohort of 32,727 women and 33,475 men

Overweight-obesity and smoking are two main preventable causes of premature death. Because the relationship between smoking and body mass index (BMI) complicates the interpretation of associations between BMI and death risks, direct estimates of risks associated with joint exposures are helpful. We have studied the relationships of BMI and smoking to middle age (40–69 years) death risk—overall and by causes—in a Norwegian cohort of 32,727 women and 33,475 men who were 35–49 years old when baseline measurements and lifestyle information were collected in 1974–1988. Individuals with a history of cancer, cardiovascular disease or diabetes at baseline were excluded. Mortality follow-up was through 2009. The relationship between BMI and middle age death risk was U-shaped. Overall middle age death risks were 11 % in women and 21 % in men. The combination of obesity and heavy smoking resulted in fivefold increase in middle age death risks in both women and men: For women middle age death risk ranged from 6 % among never smokers in the 22.5–24.9 BMI group to 31 % (adjusted 28 %) in obese (BMI > 30 kg/m²) heavy smokers (≥20 cigarettes/day). The corresponding figures in men were 10 % and 53 % (adjusted 45 %). Obese never smokers and light (1–9 cigarettes/day) smokers in the 22.5–24.9 BMI groups both experienced a twofold increase in middle age risks of death. For women, cancer (56 %) was the most common cause of death followed by cardiovascular disease (22 %). In men, cardiovascular disease was most common (41 %) followed by cancer (34 %). Cardiovascular disease deaths were more strongly related to BMI than were cancer deaths.     

The mortality risk of smoking and obesity combined

BACKGROUND: Both smoking and obesity have been linked to increased mortality, but evaluating the joint effect has been limited. This nationwide, prospective mortality study of U.S. radiologic technologists was designed to evaluate the combined mortality risks of obesity and smoking. METHODS: Mortality risk was investigated in 64,120 women and 18,760 men who completed a baseline questionnaire (1983 to 1989). Body mass index (BMI) (weight adjusted for height, or kilograms divided by meters squared) was calculated from self-reported weight and height at baseline, with five categories: less than 18.5 (underweight), 18.5 to 24.9 (normal), 25.0 to 29.9 (overweight), 30.0 to 34.9 (moderately obese), and 35.0 and higher (very obese). Participants were followed from the questionnaire until the date of death or through 2002, whichever occurred first. The combined association among BMI and smoking and all-cause, cancer, and circulatory disease mortality by gender and attained age (less than 65 years, 65 years and older) was examined using Cox proportional hazards regression analyses (conducted in 2005). Person-years at risk averaged 16 years (women aged less than 65), 6 years (women aged 65 and older), 15 years (men aged less than 65), and 7 years (men aged 65 and older), totaling 1.35 million person-years. RESULTS: In all gender/age groups, both obesity and smoking, particularly current smoking, contributed substantially to all-cause mortality, with 3.5- to 5-fold risks for very obese, current smokers compared to normal weight, never smokers. Current smoking was the predominant risk factor for cancer mortality. Combining obesity with current smoking increased circulatory disease mortality by 6- to 11-fold for people aged less than 65 years, compared to normal weight, never smokers. Obese former smokers (less than 65 years) had notably lower risks. CONCLUSIONS: Obese smokers (aged less than 65 years) had strikingly high mortality risks, particularly from circulatory disease mortality.     

Interaction between smoking and body mass index and risk of oral clefts

PurposeTo examine maternal smoking and body mass index (BMI) interactions in contributing to risk of oral clefts.MethodsWe studied 4935 cases and 10,557 controls from six population-based studies and estimated a pooled logistic regression of individual-level data, controlling for study fixed effects and individual-level risk factors.ResultsWe found a significant negative smoking–BMI interaction, with cleft risk with smoking generally declining with higher BMI. For all clefts combined, the odds ratio for smoking was 1.61 (95% confidence interval [CI]: 1.39–1.86) at BMI 17 (underweight), 1.47 (95% CI: 1.34–1.62) at BMI 22 (normal weight), 1.35 (95% CI: 1.22–1.48) at BMI 27 (overweight), 1.21 (95% CI: 1.04–1.41) at BMI 33 (obese), and 1.13 (95% CI: 0.92–1.38) at BMI 37 (very obese). A negative interaction was also observed for isolated clefts and across cleft types but was more pronounced for cleft lip only and cleft palate only.ConclusionsOur findings suggest that the risk of oral clefts associated with maternal smoking is largest among underweight mothers, although the smoking–BMI interaction is strongest for cleft lip only and cleft palate only. BMI was not protective for the effects of smoking; a clinically relevant increase in smoking-related cleft risk was still present among heavier women.     

Lifestyle factors,cardiovascular disease and all-cause mortality in middle-aged and elderly women: a systematic review and meta-analysis

Cardiovascular disease (CVD) risk factors, incidence and death increases from around the time of menopause comparing to women in reproductive age. A healthy lifestyle can prevent CVD, but it is unclear which lifestyle factors may help maintain and improve cardiovascular health for women after menopausal transition. We conducted a systematic review and meta-analysis of prospective cohort studies to evaluate the association between modifiable lifestyle factors (specifically smoking, physical activity, alcohol intake, and obesity), with CVD and mortality in middle-aged and elderly women. Pubmed, Embase, among other databases and reference lists were searched until February 29th, 2016. Study specific relative risks (RR) were meta-analyzed using random effect models. We included 59 studies involving 5,358,902 women. Comparing current versus never smokers, pooled RR were 3.12 (95% CI 2.15–4.52) for CHD incidence, 2.09 (95% CI 1.51–2.89) for stroke incidence, 2.76 (95% CI 1.62–4.71) for CVD mortality and 2.22 (95% CI 1.92–2.57) for all-cause mortality. Physical activity was associated with a decreased risk of 0.74 (95% CI 0.67–0.80) for overall CVD, 0.71 (95% CI 0.67–0.75) for CHD, 0.77 (95% CI 0.70–0.85) for stroke, 0.70 (95% CI 0.58–0.84) for CVD mortality and 0.71 (95% CI 0.65–0.78) for all-cause mortality. Comparing moderate drinkers versus non-drinkers, the RR was 0.72 (95% CI 0.56–0.91) for CHD, 0.63 (95% CI 0.57–0.71) for CVD mortality and 0.80 (95% CI 0.76–0.84) for all-cause mortality. For women with BMI 30–35 kg/m² the risk was 1.67 (95% CI 1.24–2.25) for CHD and 2.3 (95% CI 1.56–3.40) for CVD mortality, compared to normal weight. Each 5 kg/m² increase in BMI was associated with 24% (95% CI 16–33%) higher risk for all-cause mortality. This meta-analysis suggests that physical activity and moderate alcohol intake were associated with a reduced risk for CVD and mortality. Smoking and higher BMI were associated with an increased risk of these endpoints. Adherence to a healthy lifestyle may substantially lower the burden of CVD and reduce the risk of mortality among middle-aged and elderly women. However, this review highlights important gaps, as lack of standardized methods in assessing lifestyle factors and lack of accurate information on menopause status, which should be addressed by future studies in order to understand the role of menopause on the association between lifestyle factors and cardiovascular events.     

Smoking-attributable medical expenditures by age,sex, and smoking status estimated using a relative risk approach

ObjectiveTo accurately assess the benefits of tobacco control interventions and to better inform decision makers, knowledge of medical expenditures by age, gender, and smoking status is essential.MethodWe propose an approach to distribute smoking-attributable expenditures by age, gender, and cigarette smoking status to reflect the known risks of smoking. We distribute hospitalization days for smoking-attributable diseases according to relative risks of smoking-attributable mortality, and use the method to determine national estimates of smoking-attributable expenditures by age, sex, and cigarette smoking status. Sensitivity analyses explored assumptions of the method.ResultsBoth current and former smokers ages 75 and over have about 12 times the smoking-attributable expenditures of their current and former smoker counterparts 35–54 years of age. Within each age group, the expenditures of formers smokers are about 70% lower than current smokers. In sensitivity analysis, these results were not robust to large changes to the relative risks of smoking-attributable mortality which were used in the calculations.ConclusionSex- and age-group-specific smoking expenditures reflect observed disease risk differences between current and former cigarette smokers and indicate that about 70% of current smokers' excess medical care costs is preventable by quitting.     

Impact of smoking and quitting on cardiovascular outcomes and risk advancement periods among older adults

Smoking is an established risk factor for cardiovascular events, such as myocardial infarction, stroke and cardiovascular death. However, most pertinent studies primarily relied on middle aged adults. We aimed to provide empirical evidence on the association of smoking with cardiovascular events and the benefits of smoking cessation in people aged 50 years or older. In a German population-based cohort study detailed information on lifetime smoking history was obtained from 8,807 individuals aged 50–74 years, without previous myocardial infarction (MI) or stroke. Cox proportional hazards regression was applied to estimate the impact of smoking on MI, stroke and cardiovascular death (CVD) as well as on the combined outcome of major cardiovascular events (MI, stroke or CVD). In addition, the impact of smoking and the benefits of smoking cessation were quantified by risk advancement periods (RAP). The cohort included 17.2 % current smokers, 31.7 % former smokers and 51.1 % never smokers. During a mean follow-up of 9.1 years, 261 participants experienced a first MI, 456 had a primary stroke and 274 died of cardiovascular reasons. Compared to never smokers, adjusted hazard ratios (95 % confidence intervals) of current smokers were 2.25 (1.62–3.12), 2.12 (1.65–2.73) and 2.45 (1.76–3.42) and RAPs were 19.3, 9.8 and 8.4 years for MI, stroke and CVD, respectively. Strong dose–response relationships were seen with both current and life-time amount of smoking. Most of the excess risk and risk advancement disappeared within 5 years after smoking cessation. Smoking is a strong risk factor for cardiovascular events even at older age. Smoking cessation is highly and rapidly beneficial also at advanced age.     

Body mass index in young adulthood and premature death: analyses of the US National Health Interview Survey linked mortality files

Knowledge of the association between body mass index (weight (kg)/height (m)(2)) and premature death in young adulthood is very limited, especially for specific causes of death. Using the US National Health Interview Survey linked mortality files, the authors examined the relation between body mass index and premature death from all causes, cardiovascular disease (CVD), and cancer among 112,328 persons aged 18-39 years who participated in the National Health Interview Survey in the years 1987, 1988, and 1990-1995. During an average of 16 years of follow-up (ending on December 31, 2006), there were 3,178 deaths: 573 from CVD and 733 from cancer. Hazard ratios and 95% confidence intervals were estimated using multivariate proportional hazards models adjusting for age, gender, race/ethnicity, education, and smoking status. In analyses restricted to participants who had never smoked, the hazard ratios for death from all causes were 1.07 (95% confidence interval (CI): 0.91, 1.26) for overweight participants, 1.41 (95% CI: 1.16, 1.73) for obese participants, and 2.46 (95% CI: 1.91, 3.16) for extremely obese participants, compared with those of normal weight. Monotonically increasing risks for excess body weight were also observed for deaths from cancer and CVD. The associations found in this young cohort were much stronger than those in middle-aged or older populations.     

中老年男性吸烟状况与心血管疾病发生风险的关联性

  目的  探讨中老年男性吸烟状况与心血管疾病(cardiovascular disease,CVD)及其亚型发生风险的关联性。  方法  本研究选取东风-同济(Dongfeng-Tongji,DFTJ)队列中基线未患冠心病(coronary heart disease,CHD)、中风、癌症、严重心电图异常的13 940名男性为研究对象。研究对象均完成了基线调查,包括问卷调查、体格检查、生化指标检查和血液样本采集。采用Cox比例风险回归模型进行关联性分析,计算风险比(hazard ratio,HR)和95%置信区间(confidence intervals,CI)。  结果  多因素调整后,与从不吸烟者相比,现在吸烟者发生CVD、CHD和中风的风险增加,吸烟指数≥ 40包年者发生CVD、CHD和中风的风险HR值分别为1.49(95%CI:1.32~1.68,P_trend=0.001)、1.40(95%CI:1.22~1.62,P_trend=0.026)和1.59(95%CI:1.26~2.00,P_trend=0.029),开始吸烟年龄 < 20岁者发生CVD和CHD的风险HR值分别为1.29(95%CI:1.06~1.58,P_trend=0.007)和1.30(95%CI:1.03~1.64,P_trend=0.010);与现在吸烟者相比,戒烟时长≥ 10年者发生CVD和中风的风险显著降低,HR值分别为0.80(95%CI:0.71~0.91,P_trend=0.017)和0.65(95%CI:0.50~0.84,P_trend=0.207)。  结论  吸烟能增加CVD、CHD和中风的发生风险,且吸烟指数越大或开始吸烟年龄越小,CVD发生风险越高。戒烟可降低CVD和中风的发生风险。     

Effect of Age on the Association between Body Mass Index and All-Cause Mortality: The Ohsaki Cohort Study

Background

To clarify the effect of age on the association between body mass index (BMI) and all-cause mortality.

Methods

We followed 43 972 Japanese participants aged 40 to 79 years for 12 years. Cox proportional hazards regression analysis was used to estimate hazard ratios (HRs), using the following BMI categories: <18.5 (underweight), 18.5–20.9, 21.0–22.9, 23.0–24.9 (reference), 25.0–27.4, 27.5–29.9, and ≥30.0 kg/m² (obese). Analyses were stratified by age group: middle-aged (40–64 years) vs elderly (65–79 years).

Results

We observed a significantly increased risk of mortality in underweight elderly men: the multivariate HR was 1.26 (0.92–1.73) in middle-aged men and 1.49 (1.26–1.76) in elderly men. In addition, we observed a significantly increased risk of mortality in obese middle-aged men: the multivariate HR was 1.71 (1.17–2.50) in middle-aged men and 1.25 (0.87–1.80) in elderly men. In women, there was an increased risk of mortality irrespective of age group in the underweight: the multivariate HR was 1.46 (0.96–2.22) in middle-aged women and 1.47 (1.19–1.82) in elderly women. There was no excess risk of mortality with age in obese women: the multivariate HR was 1.47 (0.94–2.27) in middle-aged women and 1.26 (0.95–1.68) in elderly women.

Conclusions

As compared with the reference category, obesity was associated with a high mortality risk in middle-aged men, whereas underweight, rather than obesity, was associated with a high mortality risk in elderly men. In women, obesity was associated with a high mortality risk during middle age; underweight was associated with a high mortality risk irrespective of age. The mortality risk due to underweight and obesity may be related to sex and age.Key words: body mass index, mortality, age effect, underweight, obesity     

体重指数与死亡的前瞻性研究

目的：探讨不同体重指数（BMI）水平与总死亡及不同死因死亡的关系。方法;1982－1985年在我国不同地区的10组人群中（年龄35－39岁）进行心血管病危险因素调查,并对研究对象中无脑卒中、无心肌梗死及无恶性肿瘤史的30560人（男性15723人,女性14837人）,随访至1999－2000年,登记各种死亡的发生情况。结果：在平均15．2年的随访中,共死亡3212例,其中冠心病和脑卒中共死亡676例,恶性肿瘤死亡1281例,其他原因死亡1255例。用Cox比例风险回归模型（调整年龄、性别0估计低BMI组（BMI＜18．5）、正常BMI组（BMI为18．5－23．9）、超重组（BMI为24－27．9）和肥胖组（BMI≥28）总死亡的相对危险分别为1．21,1．00,0．901,1．12,呈“U”形关系,当同时剔除前5年死亡病例及吸烟者后,低BMI组死亡的相对危险降低,而肥胖组增加,正常BMI组的相对危险最小。 随着BMI水平的上升,冠心病和脑卒中死亡的相对危险增加,恶性肿瘤死亡的相对危险降低,其他原因死亡的相对危险与BMI水平呈“U”形关系,当剔除早期死亡病例及吸烟者后,这些趋势依然存在。结论：BMI在正常范围内,总死亡的相对危险较低,且冠心病和脑卒中死亡,恶性肿瘤死亡及其它原因死亡的 综合风险也处于相对较低水平,有着重要的公共卫生学意义。     

Association of body mass index and weight change with all-cause mortality in the elderly

The authors explored the relation of body mass index (BMI; weight (kg)/height (m)(2)) and weight change to all-cause mortality in the elderly, using data from a large, population-based California cohort study, the Leisure World Cohort Study. They estimated relative risks of mortality associated with self-reported BMI at study entry, BMI at age 21 years, and weight change between age 21 and study entry. Participants were categorized as underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), or obese (BMI >or=30). Of 13,451 participants aged 73 years (on average) at study entry (1981-1985), 11,203 died during 23 years of follow-up (1981-2004). Relative to normal weight, being underweight (relative risk (RR) = 1.51, 95% confidence interval (CI): 1.38, 1.65) or obese (RR = 1.25, 95% CI: 1.13, 1.38) at study entry was associated with increased mortality. People who were either overweight or obese at age 21 also had increased mortality (RR = 1.17, 95% CI: 1.09, 1.25). Participants who lost weight between age 21 and study entry had increased mortality regardless of their BMI category at age 21. Obesity was significantly associated with increased mortality only among persons under age 75 years and among never or past smokers. This study highlights the influence on older-age mortality risk of being overweight or obese in young adulthood and underweight or obese in later life.     

Risk assessment of physical activity and physical fitness in the Canada Health Survey mortality follow-up study.

The effect of physical fitness and physical activity on all-cause mortality and mortality due to cardiovascular disease (CVD), cancer and other causes was examined using a population-based representative sample of the Canadian population. A total of 691 deaths occurred among persons age 30-69 during the 7-year follow-up period. Of these, 37, 33 and 30% died of CVD, cancer and other causes, respectively. The effect of each risk factor on mortality was assessed using logistic regression analysis. Adjustment was made for age, sex, smoking and body mass index in the case of mortality due to CVD, all causes and causes other than CVD and cancer. Models for mortality due to cancer included adjustment for age, sex, smoking and alcohol consumption. For all cause mortality, those individuals who did not pass the physical fitness tests had significantly higher risks of death than those that passed. For CVD mortality, subjects whose physical activity was moderate were protected, and those who did not pass the physical fitness tests had substantially higher risks of death due to CVD. The risk of death due to cancer was not significantly related to physical activity or physical fitness. Persons who failed the physical fitness tests had significantly elevated risks of death due to causes other than CVD or cancer. Our findings support the conclusion that persons who are physically fit have an overall reduced risk of death independent of other major risk factors. Moderate levels of physical activity appear to be protective against cardiovascular disease.     

上海市中老年男性体重指数与死亡的前瞻性研究

目的探讨上海市区中老年男性体重指数(BMI)与死亡的关系及年龄对这种关系的影响。方法1986年1月至1989年9月调查上海市区45～64岁男性居民18244人,每年上门随访一次;用Cox比例风险模型计算相对危险度(RR)。结果至2002年度随访结束,全队列共随访235762人年,人均随访12.9年,在此期间共死亡3365人。在不吸烟者中,相对于正常BMI组(BMI18.5～23.9),低BMI组(BMI<18.5)、超重组(BMI24～27.9)和肥胖组(BMI≥28)总死亡RR值分别为1.20、1.12和1.61;在不吸烟者中去除随访开始头5年随访资料后,三组相应的RR值分别为1.01、1.12和1.75。结肠癌和心脑血管疾病死亡危险性随BMI增加而上升;除肿瘤和心脑血管疾病之外的死亡,其中主要为一些感染性疾病死亡的危险性在低BMI组显著升高,去除随访开始头5年随访资料对此结果无明显影响。在基线调查时≥55岁的对象中,肥胖组总死亡危险性上升更明显;而在<55岁的对象中,BMI与总死亡无显著相关。结论上海市区的中老年男性中肥胖会增加总死亡危险性,在年龄较大者中这种趋势更明显;结肠癌及心脑血管疾病死亡危险性随BMI增加而上升;感染性疾病的死亡危险性则在低BMI组显著升高。     

Interactions between smoking and weight in pregnancies complicated by preeclampsia and small-for-gestational-age birth

Cigarette smoking protects against preeclampsia but increases the risk of small-for-gestational-age birth (SGA). Regarding body weight, the converse is true: obesity elevates rates of preeclampsia but reduces rates of SGA. The authors assessed the combined effects of smoking and weight among US women developing preeclampsia or SGA, studying 7,757 healthy, primigravid women with singleton pregnancies in 1959-1965. Smoking (never, light, heavy), stratified by prepregnancy body mass index (BMI (weight (kg)/height (m)(2)); underweight, overweight, obese), was examined in relation to preeclampsia and SGA. Among underweight (BMI <18.5) and normal-weight (BMI 18.5-24.9) women, smoking decreased the risk of preeclampsia (for heavy smoking, light smoking, nonsmoking, test for trend p = 0.002 for underweight and p = 0.009 for normal weight) after adjustment for age, race, and socioeconomic status. However, among overweight/obese women (BMI >or=25), this trend was not apparent (p = 0.4). Among both underweight and overweight women, smoking significantly increased SGA risk (trend p < 0.001 for underweight and p = 0.02 for overweight/obese). Obesity eliminated the inverse association between smoking and preeclampsia but did not substantially alter the positive association between smoking and SGA. A possible unifying biologic explanation is discussed in this paper.     

Obesity and mortality in a prospective study of a middle-aged industrial population

BACKGROUND: Although obesity is an established risk factor for coronary heart disease and stroke mortality, its role as a risk factor for other causes of death has not been extensively investigated, particularly in an industrial population. METHODS: This prospective mortality study included 20 years of follow up of middle-aged industrial workers (n = 7139) at Shell Oil Company's manufacturing and research facilities. Baseline health risk factor data as of December 31, 1983, and mortality data as of December 31, 2003, were extracted from the company's Health Surveillance System. Relative risks (RRs) for selected causes of death by body mass index (BMI) category were calculated using the Cox proportional hazards model adjusted for age, sex, and smoking status as well as other potential risk factors, ie, cholesterol, hypertension, and fasting blood glucose. RESULTS: Compared with employees with BMI between 18.5 and 24.9 kg/m, those with BMI of 30 kg/m or greater had a statistically increased RR (adjusted for age, sex, and smoking status) for all causes (RR, 1.25; 95% confidence interval [CI] = 1.03-1.51), coronary heart diseases (RR, 2.29; 95% CI = 1.50-3.50), cardiovascular diseases (RR, 2.22; 95% CI = 1.51-3.27), diabetes (RR, 16.97; 95% CI = 2.11-136.44), and accidental deaths (RR, 2.64; 95% CI = 1.23-5.66). After adjusting for additional covariates, coronary heart diseases and cardiovascular diseases remained statistically significant. CONCLUSIONS: Obesity was associated with increased death rates for all causes, cardiovascular diseases, diabetes, and all accidents. Overweight individuals had a statistically lower cancer rate. Death rates for lung cancer and respiratory disease were lower among overweight/obese employees but did not reach statistical significance. Reductions of employee obesity can be an effective means of reducing these causes of death.     

Deaths from all causes in non-smokers who lived with smokers.

Mortality associated with passive smoking was evaluated in a 12-year study of 27,891 White adult smokers and 19,035 never smokers identified in 1963. Death rates were calculated using an estimate of the person-years at risk. Adjusted for age, marital status, education, and quality of housing, the estimated relative risks of death from all causes were 1.17 (approximate 95% confidence interval 1.01, 1.36) for men and 1.15 (1.06, 1.24) for women with passive exposure. These relative risks were similar to those for ex-smokers and for pipe or cigar smokers. Risks increased slightly with level of exposure. The relative risk from passive smoking was greatest for men under age 50 (RR = 2.09, 1.31-3.34). Risks from passive smoking were slightly elevated for several causes among men and women, and may be broader than those previously reported. On the other hand, these small nonspecific increases in death rates may reflect other characteristics of passive smokers that increase mortality.     

Age at menarche and cardiovascular disease mortality in Singaporean Chinese women: the Singapore Chinese Health Study

PurposeTo examine whether age at menarche was inversely associated with cardiovascular disease (CVD) mortality in Singaporean Chinese women.MethodsWe followed prospectively 34,022 Chinese women aged 45 to 74 at enrollment (1993–1998), with complete data on study variables, through 2009 for primary cause of death from CVD, including coronary heart disease (CHD) and cerebrovascular disease (CERE). Hazard ratios (HRs) for CVD mortality were computed across menarcheal age categories and adjusted for potential confounders and body mass index.ResultsOver 460,374 person-years of follow-up, 1852 women died from CVD, 998 from CHD and 557 from CERE. There was a significant interaction between age at menarche and smoking (P < .05). In nonsmokers, age at menarche was inversely associated with risk for CVD and CHD mortality. HRs (and 95% confidence interval) for CVD mortality across menarcheal age categories (≤12, 13–14, 15–16, ≥17) were 1.06 (0.87–1.29), 1 (referent), 0.89 (0.79–1.00), and 0.80 (0.69–0.93), respectively (P_trend < .001); HRs for CHD mortality were 1.06 (0.80–1.34), 1 (referent), 0.76 (0.65–0.90), and 0.72 (0.58–0.88), respectively (P_trend < .001). Among nonsmokers, there was no association between age at menarche and CERE mortality. Among smokers, menarcheal age was not associated with CVD, CHD or CERE mortality.ConclusionsMenarcheal age was inversely associated with risk of CVD mortality in nonsmoking Chinese women.     

R-rated film viewing and adolescent smoking

Objectives.As smoking is very common in R-rated films, we sought to determine if viewing R-rated films is associated with adolescent smoking.Methods.Three annual cross-sectional surveys conducted of 88,505 Year 10 students of largely European, Maori, Asian or Pacific Islander ethnicity in secondary schools in New Zealand between 2002 and 2004. Outcomes of interest were: intention to smoke among never smokers; past experimentation with smoking among current non-smokers; current smoking status; and current frequency of smoking.Results.Dose–response relationships were observed between the frequency of viewing R-rated films and all outcome measures controlling for age, gender, ethnicity, peer smoking, parental smoking, socioeconomic status, pocket money and household smoking rules. Compared to never viewing R-rated films, viewing at least weekly nearly tripled the relative risk (2.81; 95% confidence interval 2.57, 3.09) of never smokers being susceptible to smoking, and more than doubled the risk of both past experimentation (2.28; 95% CI 2.12, 2.45) and smoking ≥ monthly (2.31; 95% CI 2.10, 2.54). Each of these risks was seen across all ethnic groups.Conclusions.Our results extend the association that has been demonstrated between viewing R-rated films and current smoking in American youth by demonstrating the same association in youth of different ethnic and cultural backgrounds in New Zealand.     

Body mass index and mortality: a meta-analysis based on person-level data from twenty-six observational studies

PURPOSE: For this report, we examined the relationships between the conditions of being overweight and obese and mortality from all causes, heart disease, cardiovascular disease, and cancer. METHODS: We defined the categories of body weight according to level of body mass index, BMI=wt(kg)/ht(m)2, using classifications suggested by the National Institutes of Health and the World Health Organization. These classifications are as follows: "normal weight" is defined as BMI > or = 18.5, but less than 25; "overweight" equals BMI > or = 25, but less than 30; and "obese" individuals have BMIs > or = 30. Our investigation is based on person-level data from 26 observational studies that include both genders, several racial and ethnic groups, and samples from the US and other countries. The database consists of 74 analytic cohorts, arranged according to natural strata including gender, race, and area of residence. It includes 388,622 individuals, with 60,374 deaths during follow-up. We use proportional hazards models to examine the relationships between the BMI categories and mortality, controlling for age and smoking status. We use random-effects models to assess summary relative risks associated with the overweight and obesity conditions across cohorts. RESULTS: The relative risks among the heaviest individuals for overall death, death caused by coronary heart disease (CHD), and death caused by cardiovascular disease (CVD) are 1.22, 1.57, and 1.48, respectively, when compared with the those within the lowest BMI category. The summary relative risk among the heaviest participants for death from cancer is 1.07. CONCLUSIONS: We document once again, excess mortality associated with obesity. Our results do, however, question whether the current classification of individuals as "overweight" is optimal in the sense, since there is little evidence of increased risk of mortality in this group.     

中国成年人吸烟与心血管疾病发病风险的关联及其性别差异分析

目的 分析中国成年人吸烟与不同心血管疾病发病风险的关联及其性别差异。方法 研究对象来自中国慢性病前瞻性研究,基线调查开展于2004年6月至2008年7月,剔除基线自报患有恶性肿瘤、冠心病、脑卒中的个体,最终纳入487 373名研究对象。随访人年数的计算从研究对象完成基线调查时开始,至最早出现以下任一事件的时间为止：心血管疾病（CVD）发病、死亡、失访或2015年12月31日。使用Cox比例风险模型计算吸烟行为特征和心血管疾病发病风险的关联。结果 研究对象平均随访8.9年。随访期间新发缺血性心脏病33 947人,急性冠心病事件6 048人,脑内出血7 794人,脑梗死31 722人。男性吸烟率（67.9%）远高于女性（2.7%）。与非吸烟者相比,吸烟能增加各类CVD结局的发病风险,风险效应值HR值 （95%CI）由大到小依次为急性冠心病事件1.54 （1.43～1.66）、缺血性心脏病1.28 （1.24～1.32）、脑梗死1.18 （1.14～1.22）、脑内出血1.07 （1.00～1.15）。当前吸烟者中,每天吸烟量和开始吸烟年龄与急性冠心病事件风险间的关联存在性别差异（性别交互作用P值分别为0.006、0.011）,主要表现为女性吸烟者风险高于男性。每天吸烟量和开始吸烟年龄与缺血性心脏病、脑内出血和脑梗死之间的关联均未见性别差异（性别交互作用P>0.05）。结论 吸烟能够增加各类CVD的发病风险,而女性吸烟者发生急性冠心病事件的风险远高于男性。