Anthropometric predictors of coronary heart disease in Chinese women

Impacts of weight change on prehypertension in middle-aged and elderly women

BACKGROUND

Individuals with prehypertension, a new blood pressure category defined as systolic blood pressure of 120-139 mm Hg and/or diastolic blood pressure of 80-89 mm Hg, are at an increased risk for heart diseases and are strongly recommended to practice lifestyle changes, including weight control. Data on impacts of long-term weight change on prehypertension are sparse.

OBJECTIVE

To evaluate the association between weight change since age 20 and prehypertension risk.

METHODS

In this cross-sectional analysis of 36 075 non-hypertensive women aged 40-70 years, information on weight history was collected at enrollment in the Shanghai Women's Health Study; blood pressures were measured 2-3 years later by medical professionals. The odds ratios (ORs) of prehypertension were calculated for women who gained or lost weight since age 20 compared with those with stable weight (gain or loss <5 kg), adjusting for age, lifestyle factors, sodium intake and body mass index at age 20.

RESULTS

A total of 47% of the study participants (n=16 981) had prehypertension. For a 6- to 10-kg gain, the OR (95% CI) was 1.36 (1.28-1.45); for 11- to 15-kg gain, 1.64 (1.54-1.75); for 16- to 20-kg gain, 2.32 (2.14-2.51); for 21- to 25-kg gain, 2.91 (2.60-3.26); and for a gain >25 kg; 3.65 (3.13-4.26). While for a 6- to 10-kg loss and a loss >10 kg, the respective ORs were 0.76 (0.67-0.87) and 0.47 (0.38-0.59). The increase in prehypertension risk associated with each 1-kg gain was similar to that associated with a 1-year increase in age. Although weight gain during early adulthood appeared to have a more pronounced effect on the risk of prehypertension, weight gain later in life also contributed significantly to an elevated risk.

CONCLUSION

Weight gain since age 20 substantially increases risk for prehypertension in non-hypertensive individuals, while weight loss significantly lowers the risk, emphasizing the importance of weight control throughout adulthood in preventing hypertension.

Abdominal fat and risk of coronary heart disease in patients with peripheral arterial disease

OBJECTIVE

We investigated whether the presence of concomitant coronary heart disease (CHD) in patients with peripheral arterial disease (PAD) can be explained by intra-abdominal fat accumulation and compared different measures of adiposity as predictors of CHD in patients with PAD.

RESEARCH METHODS AND PROCEDURES

Data were collected from patients enrolled in the Second Manifestations of ARTerial disease (SMART) study, an ongoing prospective cohort study of patients with manifest vascular disease or vascular risk factors at the University Medical Centre Utrecht. The current analysis includes 315 patients, mean age 59 +/- 10 years, who had PAD with (n = 79) or without (n = 236) CHD. Parameters of adiposity were measured, and intra-abdominal fat and subcutaneous fat were measured ultrasonographically. Metabolic syndrome was defined according to Adult Treatment Panel III.

RESULTS

The prevalence of metabolic syndrome was higher among patients with CHD (63%) than among patients without CHD (48%). All parameters of adiposity indicated more fat in patients with CHD, except for subcutaneous fat. Waist circumference was associated with 64% higher prevalence of CHD (confidence interval, 20% to 123%) per 1 standard deviation increase in waist circumference after adjustment for age and sex. The odds ratio for waist circumference remained virtually the same after additional adjustment for the components of the metabolic syndrome and smoking.

DISCUSSION

An increased waist circumference, a crude measure of intra-abdominal fat, is associated with an increased risk of concomitant CHD in patients with PAD.

The association of meat intake and the risk of type 2 diabetes may be modified by body weight

AIM

To investigate the association between meat intake and incidence of type 2 diabetes (type 2 DM) in a large cohort of middle-aged women.

DESIGN, SUBJECTS AND METHODS

Incident cases of type 2 DM were identified during an average of 4.6 years of follow-up in a prospective cohort study of 74,493 middle-aged, Chinese women (mean age +/- SD =51.7+/- 8.97 years). Participants completed in-person interviews that collected information on type 2 DM risk factors such as dietary factors and physical activity in adulthood. Anthropometric indices were measured. Dietary intake was assessed using a validated food frequency questionnaire (FFQ). We included in the current analysis 70,609 women who had no prior history of type 2 DM at study recruitment and who had valid dietary data. The association of type 2 DM with unprocessed meat intake (g/day) and the frequency of consumption of processed meat was evaluated using the Cox model with adjustment for age, kcals/day, body mass index (BMI), waist to hip ratio (WHR), vegetable intake, smoking, alcohol consumption, physical activity, income level, education level, occupation status, and history of hypertension and chronic disease at baseline.

PRINCIPAL RESULTS

We identified 1972 incident cases of type 2 DM during a total of 326,581 person-years of follow up. Intake of unprocessed meat, particularly poultry, was associated with a decrease in the risk of type 2 DM in this cohort. The fully adjusted relative risks (RRs) for quintiles of total unprocessed meat intake were 1.00, 0.78, 0.83, 0.74, and 0.83 (P for trend: <0.01). When the joint effect between meat intake and BMI categories was evaluated, high intake of total unprocessed meat appeared to be associated with an increased risk of type 2 DM among obese women but a reduced risk among lean women (P value for the interaction tests = 0.05). Processed meat consumption was positively associated with the risk of type 2 DM. The adjusted RR was 1.15 (95% 1.01-1.32) in women consuming processed meats compared to those who did not consume processed meats (P=0.04).

CONCLUSIONS

Processed meat intake was positively associated with the risk of type 2 DM. There was an indication that the effect of unprocessed meat intake on type 2 DM may be modified by BMI.

Body weight and weight change in relation to blood pressure in normotensive men

We examined blood pressure (BP) in association with weight change since age 20, body mass index (BMI) at different ages and fat distribution in normotensive individuals using baseline survey data collected in the Shanghai Men's Health Study, an ongoing population-based prospective cohort study of Chinese men aged 40-74 years. All anthropometric and BP measurements were performed by medical professionals. Included in this analysis were 25 619 men who had no prior history of hypertension, diabetes or cardiovascular disease, never took any antihypertensive medication and had both normal systolic BP (SBP) and diastolic BP (DBP) (<140/90 mm Hg). Both SBP and DBP increased linearly across the whole range of weight gain since age 20. The adjusted mean differences between the highest and the lowest quintiles of weight gain were 6.0 mm Hg (95% confidence interval (CI): 5.6, 6.5) for SBP and 3.9 (95% CI: 3.6, 4.2) for DBP. When accounting for BMI at age 20, the multivariate-adjusted odds ratio of prehypertension (SBP, 120-139 and/or DBP, 80-89 mm Hg) was 4.1 (95% CI: 3.7, 4.5; P for trend <0.0001) comparing the extreme quintiles of weight gain. Similar positive associations were also observed for BMI at age 40, current BMI, circumferences of the waist and hips and waist-to-hip ratio. In conclusion, these data suggest that weight gain since age 20 and elevated adiposity may contribute significantly to the rise in BP in normotensive individuals, emphasizing the importance of weight control throughout adulthood in preventing high BP.

How well does the metabolic syndrome defined by five definitions predict incident diabetes and incident coronary heart disease in a Chinese population?

We evaluate the ability of the metabolic syndrome (MetS) defined by five definitions for predicting both incident CHD and diabetes combined, diabetes alone, and CHD alone in a Chinese population. The screening survey for type 2 diabetes was conducted in 1994. A follow-up study of 541 high-risk non-diabetic individuals who were free of CHD at baseline was carried out in 1999 in Beijing area. The MetS was defined by the World Health Organization (WHO), European Group for the Study of Insulin Resistance (EGIR), American College of Endocrinology (ACE), the International Diabetes Federation (IDF), and the National Cholesterol Education Program and the American Heart Association (AHA) (updated NCEP) criteria. From a multiple logistic regression adjusting for age, sex, education, occupation, smoking, family history of diabetes, and total cholesterol, the relative risk of the ACE-defined MetS for incident diabetes alone (67 cases) was 2.29 (95% CI, 1.20-4.34). The MetS defined by the five definitions was associated with a 1.8-3.9 times increased risk for both incident CHD and diabetes combined (59 cases), and with a 1.9-3.0 times for total incident diabetes (126 cases). None of the five definitions predicted either incident CHD alone (177 cases) or total incident CHD (236 cases). In conclusion, the MetS defined by the current definitions appears to be more effective at predicting incident diabetes.

Are waist circumference and body mass index independently associated with cardiovascular disease risk in Chinese adults?

BACKGROUND

In Western populations, waist circumference (WC) is more predictive of cardiovascular disease (CVD) risk than is body mass index (BMI). It is unclear whether the same is true in Asian populations.

OBJECTIVE

The objective was to examine the independent effects of WC and BMI on CVD risk factors in China.

DESIGN

CVD risk factors, BMI, and WC were measured in a nationally representative cross-sectional study of 15 540 Chinese adults aged 35-74 y.

RESULTS

Higher WC tertiles were associated with higher blood pressure and higher cholesterol, triacylglycerol, and glucose concentrations within each tertile of BMI and vice versa. In men, the odds of hypertension, dyslipidemia, and the metabolic syndrome (MS) increased with successive WC tertiles (1.0, 1.1, and 1.8, respectively, for hypertension; 1.0, 1.4, and 2.0, respectively, for dyslipidemia; and 1.0, 2.3, and 4.8, respectively, for MS; P for trend < 0.001 for all), even after adjustment for BMI. Similarly, the odds of hypertension, dyslipidemia, and MS increased with successive BMI tertiles (1.0, 1.5, and 2.6, respectively, for hypertension; 1.0, 1.3, and 1.8, respectively, for dyslipidemia; 1.0, 1.3, and 2.9, respectively for MS; P for trend < 0.001 for all), even after adjustment for WC. However, BMI tertiles were not associated with the odds of diabetes after adjustment for WC (P for trend = 0.67), whereas tertiles of WC were significantly associated with the odds of diabetes after adjustment for BMI (1.0, 1.6, and 2.1, respectively; P for trend = 0.002). The results were similar in women.

CONCLUSIONS

These data show that WC adds additional risk information to that of BMI in Chinese adults. Measurement of both WC and BMI in Chinese adults may enhance CVD risk stratification.

The Shanghai Women's Health Study: rationale, study design, and baseline characteristics

Although cancer is a major cause of morbidity and mortality in most nations, the spectrum of cancer occurrence varies substantially worldwide. Most previous epidemiologic studies investigating cancer etiology were conducted in North American and western European countries that are relatively homogenous in terms of cancer spectrums and many lifestyle exposures. These limitations may have hindered these studies from evaluating some important etiologic hypotheses. From 1996 to 2000, the Shanghai Women's Health Study recruited 74,942 adult Chinese women from selected urban communities, with a 92% response rate. All participants completed a detailed baseline survey and anthropometrics. Approximately 88% of cohort members donated a urine sample (n = 65,755) and a blood (n = 56,832) or exfoliated buccal cell (n = 8,934) sample. Noteworthy characteristics of this cohort include low consumption of alcohol (1.9%) and use of tobacco (2.4%); high intake of fish (mean, 50.8 g/day), soy foods (mean, 142.3 g/day), and certain vegetables; low prevalence of obesity (5.1%); and nearly 100% employment outside the home. Currently, this cohort of women is being followed via biennial in-person recontact and periodic linkage to cancer and vital statistics registries. The resources from the cohort will be valuable in future studies of environmental exposures and biomarkers for the risk of cancer and other chronic diseases.

Self-reported and technician-measured waist circumferences differ in middle-aged men and women

We investigated the agreement between 1) self-reported and technician-measured waist circumference at the level of the umbilicus, 2) circumference measured at the level of the umbilicus and halfway between the lower rib and the iliac crest (the natural waist), and 3) self-reported circumference at the level of the umbilicus and technician-measured circumference at the natural waist. At follow-up in the Danish "Diet, Cancer and Health" study, we recruited 176 men and 240 women for a validation study. Bland-Altman plots were used to evaluate agreement among measurement sites. Multiple regression was used to identify variables explaining the difference between measurements. The participants underestimated their waist circumference; the mean differences were -1.6 cm (95% CI: -2.4 cm, -0.8 cm) in men and -3.0 cm (95% CI: -3.8 cm, -2.3 cm) in women. Limits of agreement were from -11.9 to +8.7 cm among men and -14.9 to +8.9 cm among women. High BMI and large baseline waist circumference were associated with a larger degree of underreporting. Waist circumference measured at the level of the umbilicus was larger than at the natural waist; the mean differences were +0.7 cm (95% CI: +0.4 cm, +1.1 cm) in men and +5.0 cm (95% CI: +4.4 cm, +5.6 cm) in women. The self-reported waist circumference at the level of the umbilicus was correlated with the technician-measured circumference at the natural waist. The circumference at the natural waist was overestimated for women, depending on baseline waist circumference, and slightly underestimated for men, depending on baseline BMI.