Associations of weight loss and changes in fat distribution with the remission of hypertension in a bi-ethnic cohort: the Atherosclerosis Risk in Communities Study

Obesity related to metabolic syndrome: comparison of obesity indicators in an older french population

OBJECTIVES

Metabolic syndrome (MS) represents a cluster of metabolic abnormalities. Insulin resistance is a major component of the syndrome. We analyze in this study the relationship between body fat composition and MS in comparison to usual obesity indicators in an older adult population.

DESIGN

The PROgnostic indicator OF cardiovascular and cerebrovascular events (PROOF) study is a prospective longitudinal community cohort study among the inhabitants of Saint-Etienne, France.

METHODS

The study is a cohort study of 1011 subjects, mean age 65.6 ± 0.8 years old at inclusion, recruited from the electoral list of the town in 2000. Among them, 806 subjects realized a Dual-energy X-ray absorptiometry (DXA) used to evaluate body fat and lean mass repartition. We evaluate biological metabolic parameters according to usual techniques. The indices of obesity were calculated according to standard formula. MS presence and its components were simultaneously evaluated.

RESULTS

All obesity parameters were significantly higher (p < 0.0001) in subjects suffering metabolic syndrome as compared to those without. Body fat index (BFI) presented a stronger correlation to total fat mass, trunk fat mass and body adiposity index (BAI). The correlations between body indices and metabolic components showed that body mass index (BMI) and waist circumference were more strongly associated with BFI as compared to BAI and total fat mass. According to logistic regression analysis, only the waist-hip ratio (WHR) demonstrated a significant association with MS severity (p < 0.0001).

CONCLUSIONS

Among the obesity indices, BFI and BAI represented the best indicators to characterize global obesity while WHR only is highly predictive of metabolic syndrome presence and severity. The BAI indicator is an alternative for measuring obesity. Comparison of long-term impact of such markers on cardiovascular morbidity and mortality is now questioned.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) and hypertension risk: results of the Longitudinal Study of Adult Health (ELSA-Brasil)

We investigated whether high adherence to the Dietary Approaches to Stop Hypertension (DASH) diet was independently associated with lower risk of incident hypertension. Participants included 5632 adults, without hypertension at the baseline (2008-2010) of the Longitudinal Study of Adult Health, who took part in the second follow-up visit (2012-2014). Adherence to the DASH diet was estimated at baseline using a score based on eight food items (final scores from 8 to 40 points) and was categorised as high adherence (≥30 points, or ≥75 %) and low adherence (<75 %; reference). Hypertension was defined as systolic blood pressure (BP) ≥140 mmHg or diastolic BP ≥90 mmHg, or use of antihypertensive drugs. The association between adherence to the DASH diet and the risk of incident hypertension was estimated using Cox regression models adjusted by covariates. In total, 780 new cases of hypertension (13·8 %) were identified in about 3·8-year follow-up. Participants with high adherence to the DASH diet had 26 % lower risk of hypertension (hazard ratio (HR) 0·74; 95 % CI 0·57, 0·95) after adjustment for socio-demographic characteristics, health-related behaviours, diabetes and family history of hypertension. The HR reduced to 0·81 (95 % CI 0·63, 1·04) and was of borderline statistical significance after adjustment for BMI, suggesting that lower body weight explains about 10 % of the association between high adherence to the DASH diet and hypertension risk reduction. The results indicate that high adherence to the DASH diet lowered the risk of hypertension by one-fourth over a relatively short follow-up period.

Four-year adiposity change and remission of hypertension: an observational evaluation from the Longitudinal Study of Adult Health (ELSA-Brasil)

The degree to which weight reduction leads to the remission of hypertension in population studies is not clear. We investigated whether the changes in adiposity measures predicted the remission of hypertension in a racially admixed population over a mean 4-year follow-up. All 4847 hypertensive individuals at baseline (2008-2010) from the multicenter Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) were included. Changes in weight, waist circumference (WC), or body mass index (BMI) (reduction or increase ≥5% from baseline values, vs stability) and remission of hypertension (SBP < 140 and DBP < 90 mmHg and no use of antihypertensive medication at follow-up visit, in 2012-2014) were investigated using mixed effects logistic regression models. Proportional attributable benefit was additionally calculated. Analyses were stratified by sex and antihypertensive medication use at baseline. Remission of hypertension was 11.3% (n = 546). Among men, after adjustments, the reduction of weight (OR = 1.52 95% CI 1.10-2.10), WC (OR = 1.56 95% CI 1.04-2.35) or BMI (OR = 1.60 95% CI 1.13-2.27) was associated with the remission of hypertension. Among those not taking antihypertensive medication at baseline, after adjustments, the reduction of weight (OR = 1.64 95% CI 1.18-2.27), WC (OR = 1.76 95% CI 1.18-2.61) or BMI (OR = 1.57 95% CI 1.10-2.25) was associated with the remission of hypertension. Proportional attributable benefit among those with adiposity reduction was about 30%, indicating its potential for prevention. In conclusion, our study reinforces the role of adiposity-reducing strategies (e.g., healthy diet and regular physical activity) for the treatment and prevention of hypertension, which might have potential applications for clinical practice.

Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women

Background

Intermittent fasting (IF; severe restriction 1 d/week) facilitates weight loss and improves coronary heart disease (CHD) risk indicators. The degree to which weight loss can be enhanced if IF is combined with calorie restriction (CR) and liquid meals, remains unknown.

Objective

This study examined the effects of IF plus CR (with or without a liquid diet) on body weight, body composition, and CHD risk.

Methods

Obese women (n = 54) were randomized to either the IFCR-liquid (IFCR-L) or IFCR-food based (IFCR-F) diet. The trial had two phases: 1) 2-week weight maintenance period, and 2) 8-week weight loss period.

Results

Body weight decreased more (P = 0.04) in the IFCR-L group (3.9 ± 1.4 kg) versus the IFCR-F group (2.5 ± 0.6 kg). Fat mass decreased similarly (P < 0.0001) in the IFCR-L and IFCR-F groups (2.8 ± 1.2 kg and 1.9 ± 0.7 kg, respectively). Visceral fat was reduced (P < 0.001) by IFCR-L (0.7 ± 0.5 kg) and IFCR-F (0.3 ± 0.5 kg) diets. Reductions in total and LDL cholesterol levels were greater (P = 0.04) in the IFCR-L (19 ± 10%; 20 ± 9%, respectively) versus the IFCR-F group (8 ± 3%; 7 ± 4%, respectively). LDL peak particle size increased (P < 0.01), while heart rate, glucose, insulin, and homocysteine decreased (P < 0.05), in the IFCR-L group only.

Conclusion

These findings suggest that IF combined with CR and liquid meals is an effective strategy to help obese women lose weight and lower CHD risk.

A review of the reporting and handling of missing data in cohort studies with repeated assessment of exposure measures

BACKGROUND

Retaining participants in cohort studies with multiple follow-up waves is difficult. Commonly, researchers are faced with the problem of missing data, which may introduce biased results as well as a loss of statistical power and precision. The STROBE guidelines von Elm et al. (Lancet, 370:1453-1457, 2007); Vandenbroucke et al. (PLoS Med, 4:e297, 2007) and the guidelines proposed by Sterne et al. (BMJ, 338:b2393, 2009) recommend that cohort studies report on the amount of missing data, the reasons for non-participation and non-response, and the method used to handle missing data in the analyses. We have conducted a review of publications from cohort studies in order to document the reporting of missing data for exposure measures and to describe the statistical methods used to account for the missing data.

METHODS

A systematic search of English language papers published from January 2000 to December 2009 was carried out in PubMed. Prospective cohort studies with a sample size greater than 1,000 that analysed data using repeated measures of exposure were included.

RESULTS

Among the 82 papers meeting the inclusion criteria, only 35 (43%) reported the amount of missing data according to the suggested guidelines. Sixty-eight papers (83%) described how they dealt with missing data in the analysis. Most of the papers excluded participants with missing data and performed a complete-case analysis (n=54, 66%). Other papers used more sophisticated methods including multiple imputation (n=5) or fully Bayesian modeling (n=1). Methods known to produce biased results were also used, for example, Last Observation Carried Forward (n=7), the missing indicator method (n=1), and mean value substitution (n=3). For the remaining 14 papers, the method used to handle missing data in the analysis was not stated.

CONCLUSIONS

This review highlights the inconsistent reporting of missing data in cohort studies and the continuing use of inappropriate methods to handle missing data in the analysis. Epidemiological journals should invoke the STROBE guidelines as a framework for authors so that the amount of missing data and how this was accounted for in the analysis is transparent in the reporting of cohort studies.

Initiation of sulfonylureas versus metformin is associated with higher blood pressure at one year

PURPOSE

To determine if incident oral antidiabetic drug (OAD) use was associated with 12-month systolic blood pressure (BP) and if this was mediated through body mass index (BMI) changes.

METHODS

A retrospective cohort of veterans with hypertension who initiated metformin (n = 2057) or sulfonylurea (n = 1494) between 1 January 2000 and 31 December 2007 in the Veterans Administration Mid-South Network was assembled. Patients were included if they had complete covariates, including 12-month BP and BMI, and persisted on therapy for 12 months. Linear regression was conducted to investigate the effect of OADs on 12-month systolic BP adjusting for demographics, glycated hemoglobin, creatinine, BMI, health care utilization, and comorbidities, including cardiovascular disease (CVD). A second analysis examined if these effects were mediated by BMI change. The secondary outcome was the proportion of patients who had a controlled BP (≤ 140/90 mmHg) at 12 months adjusted for baseline BP and covariates.

RESULTS

Patients were white (82%) males (97%) with median age of 64 years (interquartile range [IQR] 57, 72), and 27% had history of CVD. Sulfonylurea users had a 1.33 mmHg (0.16, 2.50, p = 0.03) higher 12-month systolic BP than metformin users. The median change in BMI from OAD initiation to 12 months was -0.76 (IQR -1.78, 0.07) and 0.21 (IQR -0.57, 1.03) among metformin and sulfonylurea users, respectively. In a model adjusting for BMI change, the difference in 12-month systolic BP between sulfonylurea and metformin users became insignificant (0.23 (-1.00, 1.45), p = 0.72), while one BMI unit change was associated with an increase in 12-month systolic BP of 1.07 mmHg (0.74, 1.40, p < 0.0001). At 12 months, 68.3% of metformin patients had controlled BP versus 64.2% of sulfonylurea patients (p = 0.01).

CONCLUSIONS

Compared with metformin, sulfonylurea initiation was associated with increased systolic BP at 12 months, which appears to be mediated by the differential effects of these drugs on BMI.

A hypertension risk score for middle-aged and older adults

Determining which demographic and medical variables predict the development of hypertension could help clinicians stratify risk in both prehypertensive and nonhypertensive persons. Subject-level data from 2 community-based biracial cohorts were combined to ascertain the relationship between baseline characteristics and incident hypertension. Hypertension, defined as diastolic blood pressure ≥90 mm Hg, systolic blood pressure ≥140 mm Hg, or reported use of medication known to treat hypertension, was assessed prospectively at 3, 6, and 9 years. Internal validation was performed by the split-sample method with a 2:1 ratio for training and testing samples, respectively. A scoring algorithm was developed by converting the multivariable regression coefficients to integer values. Age, level of systolic or diastolic blood pressure, smoking, family history of hypertension, diabetes mellitus, high body mass index, female sex, and lack of exercise were associated with the development of hypertension in the training sample. Regression models showed moderate to high capabilities of discrimination between hypertension vs nonhypertension (area under the receiver operating characteristic curve 0.75-0.78) in the testing sample at 3, 6, and 9 years of follow-up. This risk calculator may aide health care providers in guiding discussions with patients about the risk for progression to hypertension.

Molecular determinants of the cardiometabolic phenotype

The metabolic syndrome represents a clustering of risk factors that has been shown to predict adverse cardiovascular outcomes. Although the precise mechanisms contributing to the cardiometabolic syndrome (CMS) remain poorly defined, accumulating evidence identifies two intersecting candidate pathways responsible for inflammation and energy homeostasis in the pathophysiology that underlie cardiometabolic traits. Although currently no pharmacologic interventions specifically target CMS, future drug development efforts should attempt to capitalize on molecular nodes at the intersections of these pathways in the CMS.

Increases in weight and body size increase the odds for hypertension during 7 years of follow-up

Changes in BMI and body size were compared to incident hypertension in 24,550 men and 10,111 women followed prospectively as part of the National Runners' Health Study to test whether long-term weight change affects hypertension risk. Incident hypertensions were reported by 2,143 men and 430 women during (mean +/- s.d.) 7.8 +/- 1.8 and 7.5 +/- 2.0 years of follow-up, respectively. Despite being active, men's and women's BMI increased 1.15 +/- 1.70 and 0.95 +/- 1.89 kg/m(2), respectively, and their waist circumferences increased 2.97 +/- 5.02 and 3.29 +/- 6.67 cm, respectively. Compared to those whose BMI declined, those who gained >or=2.4 kg/m(2) had an odds ratio (95% confidence interval) of 1.68 (1.45, 1.94) for becoming hypertensive if male and 1.42 (1.05, 1.92) if female. Men whose waist circumference increased >or=6 cm had an odds ratio of 1.22 (1.01, 1.47) for becoming hypertensive compared to those whose waists decreased. In both sexes, the odds for hypertension were significantly related to BMI at follow-up when adjusted for baseline BMI, but generally not to baseline BMI when adjusted for follow-up BMI. In the subset whose weights remained relatively unchanged during follow-up (+/-0.4 kg/m(2)), each kg/m(2) increment in BMI was associated with an odds ratio for becoming hypertensive of 1.19 (1.14, 1.24) in men and 1.11 (1.02, 1.20) in women. Thus, even among lean, physically active individuals: (i) weight gain increases hypertension risk; (ii) higher body weight increases the hypertension risk in a dose-dependent manner in the absence of any weight change; and (iii) there is no advantage carried forward to having been previously lean.

Changes in body weight and waist circumference affect incident hypercholesterolemia during 7 years of follow-up

OBJECTIVE

To assess whether changes in total and regional adiposity affect the odds for becoming hypercholesterolemic.

METHODS AND PROCEDURES

Changes in BMI and waist circumference were compared to self-reported physician-diagnosed hypercholesterolemia in 24,397 men and 10,023 women followed prospectively in the National Runners' Health Study.

RESULTS

Incident hypercholesterolemia were reported by 3,054 men and 519 women during (mean +/- s.d.) 7.8 +/- 1.8 and 7.5 +/- 2.0 years of follow-up, respectively. Despite being active, men's BMI increased by 1.15 +/- 1.71 kg/m2 and women's BMI increased by 0.96 +/- 1.89 kg/m2. The odds for developing hypercholesterolemia increased significantly in association with gains in BMI and waist circumferences in both sexes. A gain in BMI > or = 2.4 kg/m2 significantly (P < 0.0001) increased the odds for hypercholesterolemia by 94% in men and 129% in women compared to those whose BMI declined (40 and 76%, respectively, adjusted for average of the baseline and follow-up BMI, P < 0.0001). A gain of > or = 6 cm in waist circumference increased men's odds for hypercholesterolemia by 74% (P < 0.0001) and women's odds by 70% (P < 0.0001) relative to those whose circumference declined (odds increased 40% at P < 0.0001 and 49% at P < 0.01, respectively adjusted for average circumference). BMI and waist circumference at the end of follow-up were significantly associated (P < 0.0001) with the log odds for hypercholesterolemia in both men (e.g., coefficient +/- s.e.: 0.115 +/- 0.011 per kg/m2) and women (e.g., 0.119 +/- 0.019 per kg/m2) when adjusted for baseline values, whereas baseline BMI and circumferences were unrelated to the log odds when adjusted for follow-up values.

DISCUSSION

These observations are consistent with the hypothesis that weight gain acutely increases the risk for hypercholesterolemia.

Analysis of weight loss outcomes using VLCD in black and white overweight and obese women with and without metabolic syndrome

OBJECTIVE

To evaluate the efficacy of very low calorie diet (VLCD) in black and white obese women. Changes in weight, metabolic profile, and body composition are assessed.

METHOD

Patients are enrolled in a self-paid, university-based, outpatient weight loss program. All are prescribed VLCD (500-800 Cal/day), an exercise regimen, and group behavioral counseling. Black and white patients are matched for age, weight, body mass index, and by metabolic syndrome (MS) status.

RESULTS

A total of 304 black and white women (152 in each group) were included the analysis. Approximately 40% of patients had MS (white women: 39.5%; black women: 41.2%). Mean baseline weights were similar. After 12 weeks, weight reduction of 9.97% was seen in white women and 9.02% drop was seen in black women (both P<0.0001). However, the degree of weight change was not different between the groups (P = 0.244). Marked improvements in fasting glucose, total cholesterol, LDL, triglyceride, and blood pressures (BP) were observed (all P<0.01); however, no difference between cohorts were seen. Patients with MS had higher baseline weight, BP, glucose and triglyceride levels when compared to patients without MS (all P<0.01). Significant reductions in % body fat were seen in white and black patients, independent of MS status.

CONCLUSION

Obese patients, independent of race, were able to achieve significant weight loss when enrolled in a structured outpatient program. Weight loss significantly correlated with all aspects of MS. Our results suggest that differences seen in past studies may be influenced by socioeconomic and behavioral factors rather than differences in physiological response to dieting.