Central obesity and risk of cardiovascular disease in the Asia Pacific Region

This paper compares body mass index, waist circumference, hip circumference, and waist-hip ratio as risk factors for ischaemic heart disease and stroke in Asia Pacific populations. We undertook a pooled analysis involving six cohort studies (45 988 participants) and used Cox proportional hazards regression to assess the associations of the four anthropometric indices with stroke and ischaemic heart disease by age, sex and region. During a mean follow-up of six years, 346 stroke and 601 ischaemic heart disease events (fatal and non-fatal) were documented. Overall, a one-standard deviation increase in index was associated with an increase in risk of ischaemic heart disease of 17% (95% CI 7-27%) for body mass index, 27% (95% CI 14-40%) for waist circumference, 10% (95% CI 1-20%) for hip circumference, and 36% (95% CI 21-52%) for waist-hip ratio. There were no significant differences between age groups, sex, and region. None of the four anthropometric indices had a strong association with risk of stroke. These data indicate that measures of central obesity such as waist circumference and waist-hip ratio are strongly associated with risk of ischaemic heart disease in this region. Therefore, we suggest that, along with calculation of body mass index, measures of central obesity such as waist circumference and waist-hip ratio should be undertaken routinely.     

Comparison of Body Mass Index, Waist Circumference, and Waist/Hip Ratio in Predicting Incident Diabetes: A Meta-Analysis

Body mass index, waist circumference, and waist/hip ratio havebeen shown to be associated with type 2 diabetes. From the clinicalperspective, central obesity (approximated by waist circumferenceor waist/hip ratio) is known to generate diabetogenic substancesand should therefore be more informative than general obesity(body mass index). Because of their high correlation, from thestatistical perspective, body mass index and waist circumferenceare unlikely to yield different answers. To compare associationsof diabetes incidence with general and central obesity indicators,the authors conducted a meta-analysis based on published studiesfrom 1966 to 2004 retrieved from a PubMed search. The analysiswas performed with 32 studies out of 432 publications initiallyidentified. Measures of association were transformed to logrelative risks per standard deviation (pooled across all studies)increase in the obesity indicator and pooled using random effectsmodels. The pooled relative risks for incident diabetes were1.87 (95% confidence interval (CI): 1.67, 2.10), 1.87 (95% CI:1.58, 2.20), and 1.88 (95% CI: 1.61, 2.19) per standard deviationof body mass index, waist circumference, and waist/hip ratio,respectively, demonstrating that these three obesity indicatorshave similar associations with incident diabetes. Although theclinical perspective focusing on central obesity is appealing,further research is needed to determine the usefulness of waistcircumference or waist/hip ratio over body mass index. body fat distribution • body mass index • diabetes mellitus, type 2 • meta-analysis • obesity • waist-hip ratio     

Prospective study of snoring and risk of hypertension in women.

Whether snoring increases the risk of hypertension remains unclear. The authors examined the association between snoring and risk of hypertension in a cohort of 73,231 US female nurses aged 40-65 years and without diagnosed cardiovascular disease or cancer in 1986. Blood pressure levels and physician-diagnosed hypertension were self-reported through validated questionnaires. During 8 years of follow-up, 7,622 incident cases of physician-diagnosed hypertension were reported. Older age, smoking, body mass index, waist circumference, waist-hip ratio, weight gain, less physical activity, and sleeping on the back were directly associated with regular snoring. After adjustment for age, body mass index, waist circumference, and other covariates, snoring was associated with a significantly higher prevalence of hypertension at baseline (odds ratio = 1.22, 95% confidence interval (CI): 1.16, 1.27 for occasional snoring and odds ratio = 1.43, 95% CI: 1.33, 1.5 for regular snoring). In prospective analyses using incident cases of hypertension as the outcome, the multivariate relative risks of hypertension were 1.29 (95% CI: 1.22, 1.37) for occasional snoring and 1.55 (95% CI: 1.42, 1.70) for regular snoring. In addition, snoring was associated with significantly higher systolic and diastolic blood pressure levels. These data suggest that snoring may increase risk of hypertension in women, independent of age, body mass index, waist circumference, and other lifestyle factors.     

Waist circumference, body mass index, hip circumference and waist-to-hip ratio as predictors of cardiovascular disease in Aboriginal people

OBJECTIVE: To investigate waist circumference (WC), waist-hip ratio, hip circumference and body mass index (BMI) as risk factors for cardiovascular disease in Aboriginal Australians. METHODS: This cohort study included 836 adults aged 20-74 y in a remote Aboriginal community. WC, waist-hip ratio, hip circumference and BMI were obtained from a screening program. The participants were followed for up to 10 y for cardiovascular events. A Cox regression model was used to calculate the rate ratio (RR) and 95% confidence interval (CI) for the first-ever cardiovascular event (fatal and nonfatal). RESULTS: RRs for the first-ever cardiovascular event were 1.31 (95% CI: 1.11, 1.54), 1.29 (95% CI: 1.09,1.53), 1.28 (95% CI: 1.08, 1.52) and 1.10 (95% CI: 0.93, 1.30) per standard deviation increase in WC, BMI, hip circumference and waist-hip ratio, respectively, after adjustment for diabetes mellitus, total cholesterol, systolic blood pressure and smoking status. WC, BMI and hip circumference were significantly associated with cardiovascular risk, independent of other cardiovascular risk factors. Dividing each of the four parameters into quartiles, WC had the highest likelihood statistics (12.76) followed by BMI (11.45), hip circumference (10.57) and waist-hip ratio (3.15) for predicting first CV events. CONCLUSION: WC, BMI and hip circumference are associated with cardiovascular outcome, independent of traditional risk factors. However, WC appears to be a better predictor for cardiovascular risk than other parameters. Waist-hip ratio is not as useful as other measurements.     

Effect of adiposity and fat distribution on endometrial cancer risk in Shanghai women

The authors conducted a population-based case-control study of 832 endometrial cancer cases and 846 frequency-matched controls in Shanghai, China (1997-2001), to examine the association of overall adiposity and body fat distribution with disease risk. Overall adiposity was estimated using weight and body mass index (BMI); upper body fat distribution was evaluated using waist circumference and waist:hip ratio. Overall and upper-body obesity were both associated with an elevated risk of endometrial cancer. Adjusted odds ratios and 95% confidence intervals for highest-versus-lowest quartile comparisons were 2.6 (95% confidence interval (CI): 2.0, 3.5) for weight, 2.9 (95% CI: 2.2, 3.9) for BMI, 4.7 (95% CI: 3.4, 6.4) for waist circumference, and 3.5 (95% CI: 2.6, 4.8) for waist:hip ratio. The positive associations with weight and BMI vanished after results were controlled for waist circumference, while associations with waist circumference and waist:hip ratio persisted after adjustment for BMI. The positive association with upper-body obesity was more pronounced among younger women, women who had never used oral contraceptives, and women with a history of diabetes mellitus (p for multiplicative interaction < 0.05). Upper-body obesity was related to increased risk among women with low BMI. These results suggest that obesity, particularly upper-body fat deposition, is associated with an increased risk of endometrial cancer.     

Waist circumference, waist:hip ratio, and risk of breast cancer in the Nurses' Health Study

This study examined prospectively the associations of waist circumference and waist:hip circumference ratio with risk of breast cancer. A total of 47,382 US registered nurses who reported their waist and hip circumferences in 1986 were followed up through May 1994 for identification of incident cases of breast cancer. During 333,097 person-years of follow-up, 1,037 invasive breast cancers were diagnosed. In proportional hazards analyses, waist circumference was nonsignificantly related to risk of premenopausal breast cancer but was significantly associated with postmenopausal breast cancer after adjustment for established breast cancer risk factors (for the highest quintile of waist circumference vs. the lowest, relative risk (RR) = 1.34; 95% confidence interval (CI): 1.05, 1.72). When the analysis was limited to postmenopausal women who had never received hormone replacement therapy, a stronger positive association was found (RR = 1.88; 95% CI: 1.25, 2.85). After the data were further controlled for body mass index, the positive association was only slightly attenuated (RR = 1.83; 95% CI: 1.12, 2.99). Among past and current postmenopausal hormone users, no significant associations were found. Similar but slightly weaker associations were observed between waist:hip ratio and breast cancer risk. These data suggest that greater waist circumference increases risk of breast cancer, especially among postmenopausal women who are otherwise at lower risk because of never having used estrogen replacement hormones.     

The relations of body composition and adiposity measures to ill health and physical disability in elderly men

Although body build is related to disability and mortality in older people, the independent contributions of adiposity and lean mass are not fully defined. The authors examined the relations of body composition (fat mass index, fat-free mass index) and adiposity (body mass index, waist circumference) to ill health and physical disability in a cross-sectional study of 4,252 British men aged 60-79 years in 1998-2000. Increased body mass index, waist circumference, and fat mass index were associated with increased prevalence of cardiovascular disease, overall ill health, and disability. Adjusted odds ratios of cardiovascular disease (top vs. bottom fifth) were 1.58 (95% confidence interval (CI): 1.23, 2.03) for fat mass index, 1.45 (95% CI: 1.14, 1.86) for body mass index, and 1.27 (95% CI: 0.99, 1.62) for waist circumference. For overall "poor/fair" health, the corresponding odds ratios were 1.71 (95% CI: 1.33, 2.21), 1.49 (95% CI: 1.17, 1.90), and 1.64 (95% CI: 1.28, 2.09) and, for mobility limitation, they were 1.56 (95% CI: 1.17, 2.06), 1.96 (95% CI: 1.48, 2.56), and 1.88 (95% CI: 1.42, 2.49). A high fat-free mass index was associated with only a decreased prevalence of respiratory problems and cancer (odds ratios=0.45 (95% CI: 0.33, 0.62) and 0.62 (95% CI: 0.42, 0.94), respectively). Body fatness, not fat-free mass, is associated with cardiovascular disease and disability in older men. Simple measures of overweight, such as body mass index and waist circumference, are good indicators of the likelihood of morbidity in older men. Prevention of weight gain with increasing age is likely to reduce morbidity and disability among older men.     

Sex differences in body fat distribution and carotid intima media thickness: cross sectional survey using data from the British regional heart study

OBJECTIVE: To determine the role of central adiposity in explaining sex differences in carotid intima media thickness (IMT). DESIGN: Cross sectional survey. SETTING: Two British towns. PARTICIPANTS: 800 men and women aged 56-75 years. MAIN OUTCOME MEASURES: Carotid IMT. RESULTS: There was a continuous linear association between waist-hip ratio and IMT in both men and women. The magnitude of the association between waist to hip ratio and IMT was identical in both sexes. In age adjusted analyses IMT was 14% greater in men compared with women (age adjusted male to female ratio of geometric means 1.14; 95% confidence interval 1.07 to 1.21) with adjustment for waist to hip ratio this attenuated to no difference (1.00; 0.92 to 1.09). Adjustment for body mass index and for lifestyle risk factors had very little effect on the sex difference in mean intima media thickness. CONCLUSIONS: Sex differences in body fat distribution may explain sex differences in arterial atherosclerosis.     

左旋肉碱类膳食补充对超重肥胖成年人体格指标的影响

目的 评价左旋肉碱类膳食补充对超重肥胖成年人减重干预的有效性。方法 招募北京居住一年以上20～50岁符合标准的志愿者120名,采用随机对照研究设计,将受试者随机分组,干预组60名,对照组60名。给予干预组左旋肉碱类膳食补充,同时两组均给予健康生活宣传材料,干预期为6个月。对受试者进行基线和终期2次常规体检,包括身高、体重、腰围、臀围和体脂率。结果 干预6个月后,干预组60名研究对象的体重、腰围、臀围、体质指数(Body mass index,BMI)、腰臀比和体脂率相较于对照组有明显改善,干预组体重下降2.76(SD:1.81)kg,腰围下降4.46(SD:4.34)cm,臀围下降3.48(SD:2.65)cm,BMI下降0.99(SD:0.68)kg/m²,腰臀比下降0.01(SD:0.04),体脂率下降0.97(SD:2.00)%,干预组和对照组上述指标差异具有统计学意义(体重差值t=6.277, P<0.001; 腰围差值t=5.010, P<0.001; 臀围差值t=4.452, P<0.001; 体质指数差值t=6.264, P<0.001; 腰臀比差值t=2.347, P<0.05; 体脂率差值t=2.873, P<0.05); 不同性别之间腰臀比和体脂率变化具有差异。结论 左旋肉碱类膳食补充配合运动与健康宣教能够有效降低超重肥胖人群BMI、腰臀比和体脂率水平,为超重肥胖人群减重方法的选择提供参考。     

Cross-sectional versus prospective associations of sleep duration with changes in relative weight and body fat distribution: the Whitehall II Study

A cross-sectional relation between short sleep and obesity has not been confirmed prospectively. The authors examined the relation between sleep duration and changes in body mass index and waist circumference using the Whitehall II Study, a prospective cohort of 10,308 white-collar British civil servants aged 35-55 years in 1985-1988. Data were gathered in 1997-1999 and 2003-2004. Sleep duration and other covariates were assessed. Changes in body mass index and waist circumference were assessed between the two phases. The incidence of obesity (body mass index: > or =30 kg/m(2)) was assessed among nonobese participants at baseline. In cross-sectional analyses (n = 5,021), there were significant, inverse associations (p < 0.001) between duration of sleep and both body mass index and waist circumference. Compared with 7 hours of sleep, a short duration of sleep (< or =5 hours) was associated with higher body mass index (beta = 0.82 units, 95% confidence interval (CI): 0.38, 1.26) and waist circumference (beta = 1.88 cm, 95% CI: 0.64, 3.12), as well as an increased risk of obesity (odds ratio(adjusted) = 1.65, 95% CI: 1.22, 2.24). In prospective analyses, a short duration of sleep was not associated with significant changes in body mass index (beta = -0.06, 95% CI: -0.26, 0.14) or waist circumference (beta = 0.44, 95% CI: -0.23, 1.12), nor with the incidence of obesity (odds ratio(adjusted) = 1.05, 95% CI: 0.60, 1.82). There is no temporal relation between short duration of sleep and future changes in measures of body weight and central adiposity.     

Prospective study of abdominal adiposity and gallstone disease in US men

BACKGROUND: Obesity is an established risk factor for gallstones, but whether abdominal adiposity contributes independently to the risk, particularly in men, remains unclear. OBJECTIVE: The purpose of the study was to examine the associations of abdominal circumference and waist-to-hip ratio, as measures of abdominal adiposity, with the risk of symptomatic gallstone disease in men. DESIGN: We prospectively studied measures of abdominal obesity in relation to the incidence of symptomatic gallstone disease in a cohort of 29 847 men who were free of prior gallstone disease and who provided complete data on waist and hip circumferences. Data on weight, height, and waist and hip circumferences were collected in 1986 and in 1987 through self-administered questionnaires. As part of the Health Professionals Follow-Up Study, men reported newly diagnosed symptomatic gallstone disease on questionnaires mailed to them every 2 y. RESULTS: We documented 1117 new cases of symptomatic gallstone disease during 264 185 person-years of follow-up. After adjustment for body mass index and other known or suspected risk factors for gallstones, men with a height-adjusted waist circumference > or = 102.6 cm (40.4 in) had a relative risk of 2.29 (95% CI: 1.69, 3.11; P for trend < 0.001) compared with men with a height-adjusted waist circumference < 86.4 cm (34 in). Men with a waist-to-hip ratio > or = 0.99 had a multivariate relative risk of 1.78 (1.38, 2.28; P for trend < 0.001) compared with men with a waist-to-hip ratio < 0.89. CONCLUSIONS: Our data suggest the presence of a significant association between abdominal adiposity and the incidence of symptomatic gallstone disease. As measures of abdominal adiposity, abdominal circumference and waist-to-hip ratio predict the risk of developing gallstones independently of body mass index.     

The relation of body fat distribution and body mass with haemoglobin A1c, blood pressure and blood lipids in urban Japanese men

The relation of body fat distribution and body mass with haemoglobin A1c, blood pressure and blood lipids were examined in 874 men aged 40 to 59 not taking medication for diabetes mellitus and who worked for an urban company in Japan. Body fat distribution was measured by the waist hip circumference ratio. Body mass was estimated by Quetelet index. Haemoglobin A1c was measured from casual venous blood samples by high-pressure liquid chromatography. Measurement of haemoglobin A1c was validated by a 75 g oral glucose tolerance test conducted in a 7% sample. There was a dose-response relation between waist-hip ratio and haemoglobin A1c concentration while the relation between body mass index and haemoglobin A1c was not evident. Using linear regression to control for age, serum total cholesterol, usual alcohol consumption, cigarette smoking and body mass index, the positive association between waist-hip ratio and haemoglobin A1c remained significant (p = 0.02). This was not true for the positive association between body mass index and haemoglobin A1c (p = 0.32). Both waist-hip ratio and body mass index were positively associated with blood pressure and serum total cholesterol, and inversely associated with HDL-cholesterol. The associations of waist-hip ratio with blood pressure and blood lipids were significant after controlling for body mass index. Therefore, the waist-hip ratio is a correlate of both glucose abnormalities and known coronary risk factors in urban Japanese men even when body mass is controlled for.     

Waist circumference and mortality

The authors examined the association between waist circumference and mortality among 154,776 men and 90,757 women aged 51-72 years at baseline (1996-1997) in the NIH-AARP Diet and Health Study. Additionally, the combined effects of waist circumference and body mass index (BMI; weight (kg)/height (m)(2)) were examined. All-cause mortality was assessed over 9 years of follow-up (1996-2005). After adjustment for BMI and other covariates, a large waist circumference (fifth quintile vs. second) was associated with an approximately 25% increased mortality risk (men: hazard ratio (HR) = 1.22, 95% confidence interval (CI): 1.15, 1.29; women: HR = 1.28, 95% CI: 1.16, 1.41). The waist circumference-mortality association was found in persons with and without prevalent disease, in smokers and nonsmokers, and across different racial/ethnic groups (non-Hispanic Whites, non-Hispanic Blacks, Hispanics, and Asians). Compared with subjects with a combination of normal BMI (18.5-<25) and normal waist circumference, those in the normal-BMI group with a large waist circumference (men: > or =102 cm; women: > or =88 cm) had an approximately 20% higher mortality risk (men: HR = 1.23, 95% CI: 1.08, 1.39; women: HR = 1.22, 95% CI: 1.09, 1.36). The finding that persons with a normal BMI but a large waist circumference had a higher mortality risk in this study suggests that increased waist circumference should be considered a risk factor for mortality, in addition to BMI.     

Larger hip circumference independently predicts health and longevity in a Swedish female cohort

OBJECTIVE: The waist circumference is widely viewed as a simple but effective measure for assessing obesity-related health risks, whereas measurement of the hip circumference is not currently prioritized. This study examines health risks associated specifically with hip circumference in a cohort of Swedish women, to determine whether information may be lost by excluding the hip circumference from health surveys. RESEARCH METHODS AND PROCEDURES: The subjects described in this report constitute a population-based sample of 38- to 60-year-old women who underwent anthropometric examinations in 1968. The 24-year incidence rates have been ascertained for myocardial infarction, combined cardiovascular diseases, and diabetes. All-cause, cardiovascular, and myocardial infarction mortality also were evaluated. RESULTS: Hip circumference was a significant independent inverse risk estimator for all endpoints studied. Using Cox regression with adjustment for age, smoking, body mass index, and waist circumference, the remaining variability associated with larger hips was associated with significantly fewer adverse health outcomes. The hip circumference became statistically informative after body mass index adjustment. The strongest protective associations were observed for cardiovascular disease and diabetes endpoints, although significant trends were also seen for total mortality. Considering hip and waist simultaneously, the strength of the inverse association for large hips generally exceeded the positive association for waist. DISCUSSION: Recent interest in the waist circumference as an effective screening tool has taken the focus off of the hip circumference. The present results suggest that collection of hip measurements should not be discontinued in assessment of obesity-related risk status and health promotion.     

A randomized trial of lifestyle intervention in primary healthcare for the modification of cardiovascular risk factors

AIMS: To evaluate the effects of a lifestyle intervention programme in primary healthcare, targeted to patients with moderate to high risk of cardiovascular disease in terms of cardiovascular risk factors, physical activity, and quality of life. METHOD: Randomized controlled trial with one-year follow-up, carried out in a primary healthcare centre in Northern Sweden. A total of 151 middle-aged men and women, with hypertension, dyslipidemia, type 2 diabetes, or obesity were enrolled. The subjects were randomized to either the intervention (n = 75) or the control group (n = 76). A total of 123 subjects completed the one-year follow-up. Interventions: Exercise: supervised endurance and circuit training in groups three times a week for three months. Diet: five group sessions of diet counselling with a dietitian. Follow- up meetings with a physiotherapist were conducted monthly thereafter. Primary outcomes were changes in anthropometry, maximal oxygen uptake, health-related quality of life, and self-reported physical activity. The secondary outcomes were changes in blood pressure and metabolic variables. RESULTS: After one year the intervention group significantly increased maximal oxygen uptake, physical activity, and quality of life and significantly decreased body weight, waist and hip circumference, body mass index, waist-hip ratio, systolic and diastolic blood pressure, triglycerides, and glycosylated haemoglobin. There were significant differences between groups, mean changes (and their 95% confidence intervals, CI) in waist circumference -1.9 cm (-2.80 to -0.90; p<0.001), in waist-hip ratio -0.01 (-.02 to -0.004; p<0.01) and in diastolic blood pressure -2.3 mmHg (-4.04 to -0.51; p<0.05). CONCLUSION: A prevention programme in primary healthcare with a focus on physical activity and diet counselling followed by structured follow-up meetings can favourably influence several risk factors for cardiovascular diseases and quality of life in high-risk subjects for at least one year.     

人体测量指标与中小学生胰岛素抵抗的相关性研究

目的 了解体质指数(BMI)、腰围、腰臀比(WHR)及脂肪率与中小学生胰岛素抵抗的相关性。方法 测量247例中小学生身高、体重、腰围、臀围、脂肪率(%BF),计算BMI、WHR,测量其空腹血糖(FBG)及空腹胰岛素(FIN),通过稳态模型法(HOMA)计算胰岛素抵抗(IR)指数(HOMA-IR),评价胰岛素敏感性;通过ROC曲线下面积评价各项指标对IR的预测效能,并计算出相应指标的特异度及灵敏度,两者同时最大的点作为各项指标的切点。结果 ROC曲线下面积、切点分别为:BMI 0.771、27.45,WHR 0.681、0.923,腰围0.777、86.5 cm,%BF 0.66%、26.85%。结论 腰围、BMI、WHR、脂肪率均可作为预测IR的参考指标,腰围和BMI为最佳指标。     

The associations of physical activity and adiposity with alanine aminotransferase and gamma-glutamyltransferase

The mechanisms linking obesity and inactivity to diabetes mellitus are unclear. Recent studies have shown associations of alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) with diabetes. In a random sample of 3,789 British women aged 60-79 years, the authors examined the associations of obesity and physical activity with ALT and GGT (1999-2001). Both body mass index and waist:hip ratio were independently (of each other, physical activity, alcohol consumption, smoking, and childhood and adulthood social class) positively and linearly associated with ALT and GGT. In adjusted models, a one-standard-deviation increase in body mass index was associated with a 0.46-units/liter (95% confidence interval (CI): 0.16, 0.75) increase in ALT and a 2.14-units/liter (95% CI: 0.99, 3.30) increase in GGT. Similar results for a one-standard-deviation increase in waist:hip ratio were 13.96 (95% CI: 10.44, 17.48) for ALT and 39.44 (95% CI: 25.89, 52.98) for GGT. Frequency of physical activity was inversely and linearly associated with GGT in fully adjusted models, but the inverse association with ALT was attenuated towards the null after adjustment for body mass index and waist:hip ratio. Adjustment for ALT and GGT resulted in some attenuation of the strong linear associations of body mass index and waist:hip ratio with diabetes. These findings provide some support for the suggestion that the relation between obesity and diabetes is, at least in part, mediated by liver pathology.     

锥形束CT引导下宫颈癌患者个体因素与摆位误差的相关性分析

目的:探讨锥形束CT(CBCT)引导下宫颈癌患者的个体因素及其变化与摆位误差之间的相关性。方法:选取在医院就诊且行放射治疗的23例宫颈癌患者,采用CT模拟定位时测量患者身高、体质量、腰围以及臀围与膀胱容量,并计算体质量指数(BMI);放射治疗前进行CBCT扫描获取容积图像与计划CT图像进行配准,并同步测量患者身高、体质量、腰围以及臀围与膀胱容量,每例患者进行6~9次CBCT验证,共计验证188次,计算每次治疗与定位时患者体质量、膀胱容量与腰臀围的变化量,记录左右(x轴)、头脚(y轴)和前后(z轴)3个轴向的线性误差,以及对应的旋转摆位误差(xr、yr和zr)。应用Pearson相关分析法分析患者个体因素与摆位误差之间的关系。结果:宫颈癌患者膀胱容量、BMI、体质量与摆位总误差具有相关性(r=0.285,r=0.236,r=0.156;P<0.05);患者个体因素的变化与旋转误差有相关性,体质量与腰臀围的变化影响y轴的旋转误差,腰臀围的变化影响z轴的旋转误差;体质量与臀围的变化影响z轴的线性误差;而个体膀胱容量的变化与摆位误差之间无相关性。头脚方向的水平线性误差显著大于其他方位,而对应的旋转误差显著高于前后方向的旋转误差。结论:CBCT引导宫颈癌患者放射治疗时,应考虑患者的身高、体质量、腰围和膀胱容量及其变化量等影响因素,需制定个性化的化临床靶区体积(CTV)至计划靶区体积(PTV)外扩边界,体位固定时应注意患者头脚方向的固定,以降低误差提高放射治疗精度。     

Waist and hip circumferences have independent and opposite effects on cardiovascular disease risk factors: the Quebec Family Study

BACKGROUND: A high waist-to-hip ratio is associated with unfavorable cardiovascular disease risk factors. This could be due to either a relatively large waist or a small hip girth. OBJECTIVE: We sought to define the separate contributions of waist girth, hip girth, and body mass index (BMI) to measures of body composition, fat distribution, and cardiovascular disease risk factors. DESIGN: Three-hundred thirteen men and 382 women living in the greater Quebec City area were involved in this cross-sectional study. Percentage body fat, anthropometric measurements, and abdominal fat distribution were obtained and BMI (in kg/m2) and waist-to-hip ratio were calculated. Serum blood lipids were determined from blood samples collected after subjects had fasted overnight RESULTS: A large waist circumference in men and women (adjusted for age, BMI, and hip circumference) was associated significantly with low HDL-cholesterol concentrations (P < 0.05) and high fasting triacylglycerol, insulin, and glucose concentrations (P < 0.01). In women alone, a large waist circumference was also associated with high LDL-cholesterol concentrations and blood pressure. A narrow hip circumference (adjusted for age, BMI, and waist circumference) was associated with low HDL-cholesterol and high glucose concentrations in men (P < 0.05) and high triacylglycerol and insulin concentrations in men and women (P < 0.05). Waist and hip girths showed different relations to body fat, fat-free mass, and visceral fat accumulation. CONCLUSIONS: Waist and hip circumferences measure different aspects of body composition and fat distribution and have independent and often opposite effects on cardiovascular disease risk factors. A narrow waist and large hips may both protect against cardiovascular disease. These specific effects of each girth measure are poorly captured in the waist-to-hip ratio.