Adiposity measurements by BMI, skinfolds and dual energy X-ray absorptiometry in relation to risk markers for cardiovascular disease and diabetes in adult males

The Mediation and Moderation Effect Association among Physical Activity, Body-Fat Percentage, Blood Pressure, and Serum Lipids among Chinese Adults: Findings from the China Health and Nutrition Surveys in 2015

Physical activity (PA) is of benefit and particularly important for cardiovascular disease risk factors as being sedentary becomes a lifestyle habit. Research into Chinese complex association among physical activity, body-fat percentage (BF%), blood pressure, and serum lipids is limited. The present study is based on an observational study among adults (>18 years old) residing in fifteen provinces in China. Data of 10,148 adult participants in the 2015 China Health and Nutrition Survey (CHNS) were analyzed. The simple mediation effect models with covariates were utilized to assess the association among PA and blood pressure or serum lipids, and BF% was played as a mediator. The serial multiple-mediator models with covariates were constructed to the further analysis of the relationship between PA and blood pressure, and BF% was the mediator 1 and blood lipids were the mediator 2. Based on the above hypothesis, the moderated mediation models with covariates were used to analyze the association among PA, BF%, and blood pressure; in addition, BF% was used as the mediator and blood lipids played as the moderator. In the simple mediation models, the model with a dependent variable was high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C); BF% was played as the partly mediation effect and the proportion of contribution was 0.23 and 0.25, respectively. In the serial multiple-mediator models, blood lipids, as the second mediator, played the mediation effect; however, the effect was smaller than the BF%. In the moderated mediation model, blood lipids had the moderation effect as the moderator variable. HDL-C played a moderating role in the latter pathway of the "PA→BF%→SBP/DBP" mediation model, and LDL-C/TC played a moderating role in the direct effect of the "PA→BF%→DBP". In conclusion, BF% played a mediating role in the relationship between PA and blood pressure. HDL-C, LDL-C, and TC were more likely to act as moderating variables in the mediation model "PA→BF%→SBP/DBP". PA could directly and indirectly benefit to control the CVD risk factors simultaneously.

Risk Factors for Cardiometabolic Disease in Professional Firefighters

OBJECTIVE

Firefighters are plagued with cardiometabolic disease (CMD). Obesity, poor cardiorespiratory and muscular fitness, and blood lipids (low-density lipoprotein cholesterol, triglycerides, low high-density lipoprotein cholesterol) are risk factors for CMD. However, markers of oxidative stress, inflammation, and insulin resistance can provide further insight regarding CMD risk.

METHODS

This study investigated the relationships between fitness metrics (cardiorespiratory and muscular fitness, percent body fat, waist circumference), blood lipids, blood pressure, and years of experience as a firefighter to blood markers of insulin resistance: Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), oxidative stress: advanced oxidation protein products (AOPPs), and inflammation: C-reactive protein.

RESULTS

Waist circumference and blood concentrations of triglycerides were significantly related to AOPPs and HOMA-IR. Cardiorespiratory fitness was inversely related to AOPPs, HOMA-IR and C-reactive protein.

CONCLUSION

These findings demonstrate the importance of high cardiorespiratory fitness and low waist circumference to reduce markers of CMD.

Healthy cardiovascular biomarkers across the lifespan in wild-born chimpanzees (Pan troglodytes)

Chimpanzees (Pan troglodytes) are a crucial model for understanding the evolution of human health and longevity. Cardiovascular disease is a major source of mortality during ageing in humans and therefore a key issue for comparative research. Current data indicate that compared to humans, chimpanzees have proatherogenic blood lipid profiles, an important risk factor for cardiovascular disease in humans. However, most work to date on chimpanzee lipids come from laboratory-living populations where lifestyles diverge from a wild context. Here, we examined cardiovascular profiles in chimpanzees living in African sanctuaries, who range semi-free in large forested enclosures, consume a naturalistic diet, and generally experience conditions more similar to a wild chimpanzee lifestyle. We measured blood lipids, body weight and body fat in 75 sanctuary chimpanzees and compared them to publicly available data from laboratory-living chimpanzees from the Primate Aging Database. We found that semi-free-ranging chimpanzees exhibited lower body weight and lower levels of lipids that are risk factors for human cardiovascular disease, and that some of these disparities increased with age. Our findings support the hypothesis that lifestyle can shape health indices in chimpanzees, similar to effects observed across human populations, and contribute to an emerging understanding of human cardiovascular health in an evolutionary context. This article is part of the theme issue 'Evolution of the primate ageing process'.

Comparison of 7-site skinfold measurement and dual-energy X-ray absorptiometry for estimating body fat percentage and regional adiposity in Taiwanese diabetic patients

Obesity and regional adiposity are important risk factors for cardiometabolic disorders. The aim of this study is to compare 7-site skinfold (SF) measurement to dual-energy x-ray absorptiometry (DXA) as the reference method for estimating body fat percentage (BF%) and regional adiposity in diabetic outpatients. A total of 59 diabetic patients (36 females and 23 males) aged 28.5–78 years (median 67.7 years) with BMI 18.8–40.6 kg/m² (median: 25.5 kg/m²) were enrolled. 7-site skinfold measurement and DXA were performed at the same visit day and biochemistry data were collected. Our results demonstrate the BF% calculated via Jackson & Pollock 7-site skinfold equation presents a strong correlation (r = 0.672, p < 0.001 in females; r = 0.885, p < 0.001 in males) with that measured by DXA, but the means of BF% between these two methods are significantly different in both sexes (paired t-test, p < 0.001). The Bland-Altman analysis showed the mean differences (DXA-SF) of BF% were positive for female (8.74%) and male (7.22%), suggesting Jackson & Pollock 7-site skinfold equation tends to underestimate the BF%. Besides, regional SF thicknesses of 7-site skinfold measurement were significantly correlated with the matched regional adiposity quantified by DXA. Furthermore, truncal and android SF thicknesses were notably positively correlated with several cardiometabolic risk factors in gender-specific manner. Our data indicate the 7-site skinfold measurement is not an interchangeable method for precisely measuring BF%, but might be practical for evaluating the cardiometabolic risks in Taiwanese diabetic outpatients.

Adiposity Indicators as Cardio-Metabolic Risk Predictors in Adults from Country with High Burden of Obesity

BACKGROUND

In Qatar more than 70% 0f the adults are overweight and obese. Different adiposity assessment methods have been proposed to identify individuals at cardio-metabolic risk.

PURPOSE

This study aimed to compare anthropometric indicators with Dual-energy X-ray absorptiometry (DXA) -derived adiposity indicators in predicting cardio-metabolic risk among Qatari adults.

PATIENTS AND METHODS

A random sample of five hundred and fifty-eight (558) healthy Qatari adults (men and women) aged 20 to 50 years was obtained from Qatar Biobank survey data. Anthropometric data (weight, height, and waist circumference), the DXA-derived data, and cardio-metabolic (CM) risk parameters were analyzed. A Spearman partial correlation coefficient, Receiver Operating Characteristics (ROC) curve and an area under curve (AUC) were used to assess the predicting ability of adiposity indicators for CM risk factors.

RESULTS

Adiposity indices (anthropometric and DXA) were significantly correlated with most of the CM indicators (r= -0.292 to 0.486, p< 0.001). The AUC of waist to height ratio (WHtR) was significantly higher than that of body mass index (BMI) and waist circumference (WC) in the prediction of low high density lipoprotein (HDL) (AUC=0.65, AUC=0.59; AUC=0.64), high low density lipoprotein (LDL) (AUC=0.67; AUC=0.62; AUC=0.66), high cholesterol (AUC=0.66; AUC=0.63; AUC=0.63), and high Homeostatic Model Assessment- (HOMA) (AUC= 0.81; AUC= 0.78; AUC=0.78). Among DXA- parameters, trunk fat had the highest AUCs for total cholesterol (AUC= 0.64, CI=0.56, 0.73), triglycerides and glucose index (TyG) (AUC=0.69, CI=0.64, 0.74), and HOMA (AUC=0.78, CI= 0.73, 0.84).

CONCLUSION

Results of the present study show that adiposity indicators (WC and WHtR) are clinically valuable tools to identify individuals at risk of CVD compared to DXA-derived parameters, while DXA can provide more accurate estimates.

Women Are at a Higher Risk of Chronic Metabolic Diseases Compared to Men With Increasing Body Mass Index in China

Background: Chronic non-communicable diseases are the major causes of mortality in the world. However, few studies have investigated the association between multi-categories BMI and chronic diseases from perspective of sex stratification. This study aimed to investigate the risk of chronic diseases at different BMI levels, and to further explore whether BMI-health risk associations differ by sex. Methods: In total, 21,134 participants aged 19-65 years (60.4% men) from the Tianjin People's Hospital, Tianjin Union Medical Center-Health Management Center were recruited for this cross-sectional study. Sex-specific percentiles of BMI were calculated and divided into 11 categories according to the 2000 CDC growth charts. Health-related indicators, such as hyperglycemia, hypertension, non-alcoholic fatty liver diseases (NAFLD), hyperuricemia, etc., were used as dependent variables in this study. Statistical differences were tested by unpaired Mann-Whitney U-test and chi-squared test. Logistic regression models were used to examine the associations between BMI and health-related indicators. Results: The risk of hyperglycemia (OR: 1.67, 95%CI: 1.23-2.29), NAFLD (OR: 2.22, 95%CI: 1.74-2.85), hypertriglyceridemia (OR: 1.65, 95%CI: 1.28-2.12), and hyperuricemia (OR: 1.39, 95%CI: 1.12-1.72) in men began to increase significantly when BMI was in the range of 22.59-23.89 kg/m². However, in women, the risk of hyperglycemia (OR: 3.02, 95%CI: 1.25-8.98) and hyperuricemia (OR: 1.94, 95%CI: 1.26-3.05) began to increase significantly when BMI was in the range of 22.76-23.62 kg/m², and the risk of NAFLD (OR: 5.48, 95%CI: 2.49-14.47) began to increase significantly when BMI was in the range of 21.08-21.97 kg/m². Besides, at the same BMI level, the risk of diseases in women were significantly higher than that in men, especially when BMI > 25 kg/m². Conclusion: In the Chinese population, the risk of chronic diseases in women were significantly higher than that in men at the same BMI level, especially when BMI was >25 kg/m². In addition, the risk of chronic diseases began to increase significantly when BMI was >21.97 kg/m² in women and 23.89 kg/m² in men. The results indicated that women should be more alert to the risk of chronic diseases caused by the increase of BMI than men.

Independent relationships between bone mineral density, regional body fat and insulin sensitivity in white males

BACKGROUND

Adiposity and insulin sensitivity may affect bone mineral density (BMD), but the confounding effect of weight hinders discrimination of independent associations. We explored whether regional fat masses and insulin sensitivity are independently related to BMD.

MATERIALS AND METHODS

Relationships between total and regional body fat, insulin sensitivity and measures of BMD in 8 different regions were evaluated in a cross section of 590 generally healthy, white males, 274 of whom received measurement of insulin sensitivity (Si) using the intravenous glucose tolerance test. Measurements included total, android and gynoid fat and lean body mass and regional BMDs by dual-energy X-ray absorptiometry. Linear regression analyses were combined in a mediation analysis to explore associations with each regional BMD.

RESULTS

Weight correlated positively with total fat mass (R²  = 0.67, P < 0.001) and negatively with Si (R²  = 0.14, P < 0.001). Body composition measures were consistently positively related to BMD in all regions except lumbar and thoracic spine. Accounting for body weight rendered negative majority of associations between total and regional fat masses and BMDs. An independent association between android fat and spine BMD was particularly apparent. Si was positively associated with total and limb BMD (P < 0.01) specifically among exercisers. Accounting for Si diminished the associations of total fat (negative) and lean body mass (positive) with total and limb BMD.

CONCLUSION

Android fat is independently negatively associated with spine BMD. Among those taking exercise, increased insulin sensitivity is associated with higher limb BMD and may underlie positive associations between lean body mass and BMD.

The Plausibility of Obesity Paradox in Cancer-Point

In contrast to the convincing evidence that obesity (measured by body mass index, BMI) increases the risk of many different types of cancer, there is an ambiguity in the role of obesity in survival among cancer patients. Some studies suggested that higher BMI decreased mortality risk in cancer patients, a phenomenon called the obesity paradox. The spurious positive association between BMI and cancer survival is likely to be explained by several methodologic limitations including confounding, reverse causation, and collider stratification bias. Also, the inadequacy of BMI as a measure of body fatness in cancer patients commonly experiencing changes in body weight and body composition may have resulted in the paradox. Other factors contributing to the divergent results in literature are significant heterogeneity in study design and method (e.g., study population, follow-up length); time of BMI assessment (pre-, peri-, or post-diagnosis); and lack of consideration for variability in the strength and directions of associations by age, sex, race/ethnicity, and cancer subtype. Robust but practical methods to accurately assess body fatness and body compositions and weight trajectories in cancer survivors are needed to advance this emerging field and to develop weight guidelines to improve both the length and the quality of cancer survival. Cancer Res; 78(8); 1898-903. ©2018 AACR.

Correlation between DXA and laboratory parameters in normal weight, overweight, and obese patients

OBJECTIVE

The aim of this study was to review the existence and types of correlations between body composition densitometric parameters and laboratory values associated to cardiometabolic risk.

METHODS

We retrospectively analyzed data from 316 individuals in the weight range from normality to super-obesity, submitted to total body dual-energy x-ray absorptiometry (DXA) scans and routine biochemistry at S.Orsola-Malpighi Hospital from June 2010 to March 2014. The study included 182 women, 45.8 ± 13.4 y of age, with a body mass index (BMI) of 31.5 (± 11) kg/m² (group F) and 134 men, 45.4 ± 13.6 y of age, with a BMI of 27.6 (± 7.8) kg/m² (group M). All patients underwent whole-body scan (Lunar iDXA, GE Healthcare, Madison, WI, USA) and laboratory analysis (blood fasting glucose, total cholesterol, high-density lipoprotein cholesterol, tricylglycerides [TGs], aspartate aminotransferase, and alanine aminotransferase). Correlation between laboratory values and total body and regional fat mass (including visceral adipose tissue [VAT] and subcutaneous adipose tissue in the android region), and lean mass parameters were analyzed with linear and stepwise regressions analysis (significance limit, P < 0.05). Receiver operating characteristic curves were performed to assess the accuracy of the best-fit DXA parameter (VAT) to identify at least one laboratory risk factor.

RESULTS

In both groups, BMI and densitometric parameters showed a linear correlation with fasting blood glucose and TG levels and an inverse correlation with high-density lipoprotein cholesterol (P < 0.05), whereas no correlation was observed with total cholesterol levels. The only densitometric parameter retained in the final model of stepwise multiple regression was VAT for fasting blood glucose (group F: β = 0.4627, P < 0.0001; group M: β = 0.6221, P < 0.0001) and TG levels (group F: β = 0.4931, P < 0.0001; group M: β = 0.1990, P < 0.0261) independently of BMI. The optimal cutoff points of VAT to identify the presence of at least one laboratory risk factor were >1395 g and >1479 cm³ for men and >1281 g and >1357 cm³ for women.

CONCLUSIONS

DXA analysis of VAT is associated with selected laboratory parameters used for the evaluation of cardiometabolic risk and could be per se a helpful parameter in the assessment of clinical risk.

Skinfold thickness measurements and mortality in white males during 27.7 years of follow-up

INTRODUCTION

Obesity is a major risk factor for mortality from a range of causes. We investigated whether skinfold measurements were associated with mortality independently of variation in body mass index (BMI).

METHODS

A prospective analysis of mortality in 870 apparently healthy adult Caucasian men participating in an occupational health cohort was undertaken. At baseline, skinfold measurements were taken at biceps, triceps, iliac and subscapular sites. Derived measurements included the sum of all four skinfolds and subscapular to triceps, subscapular to iliac and BMI to iliac ratios. All-cause mortality was analysed by Cox proportional hazards modelling and death in specific mortality subcategories by competing risks analysis.

RESULTS

During a mean of 27.7 years follow up, there were 303 deaths (119 cancer, 101 arteriovascular, 40 infection, 43 other). In univariable analysis, BMI was associated with all-cause, cancer, arteriovascular and other mortality and subscapular skinfold with all-cause and arteriovascular mortality. On bivariable analysis, with inclusion of BMI, subscapular skinfold ceased to be a associated with mortality but iliac skinfold emerged as strongly, negatively associated with all-cause and arteriovascular mortality. In multivariable analysis, with inclusion of age, BMI, smoking, alcohol and exercise, iliac skinfold was negatively associated with all-cause (Hazard ratio HR 0.77, 95% confidence interval CI 0.66-0.90, p = 0.002), arteriovascular (HR 0.75, 95%CI 0.58,0.97, p = 0.02) and infection (HR 0.63, 95%CI 0.42,0.94, p = 0.02) death. Among obese participants (BMI ≥ 30 kg/m²), iliac skinfold of ≤9.7 mm was associated with a six-fold increase in all-cause mortality risk.

CONCLUSION

Low iliac skinfold thickness is an independent risk factor for all-cause mortality in adult white males with risk apparently concentrated among people who are obese.

Comparison between dual-energy X-ray absorptiometry and skinfold thickness in assessing body fat in overweigh/obese adult patients with type-2 diabetes

Percentage of body fat (%BF) is estimated in clinical practice using anthropometric equations, but little is known about their reliability in overweight/obese patients with type-2 diabetes. The aim of this study was to compare, in overweight/obese adults with type-2 diabetes, %BF estimated with several commonly used anthropometric equations and %BF measured with dual-energy X-ray absorptiometry (DXA, Hologic). The %BF was measured with DXA in 40 patients aged 40-68 years with type-2 diabetes (mean HbA1c, 7.3 ± 0.9%). Body density was estimated in the same patients by means of four anthropometric equations and converted to %BF using the Siri and Brozek equations. Paired-sample t-test and the mean signed difference procedure were used to compare anthropometric equation-derived %BF and DXA measurements. The coefficient of determination was computed. Bland-Altman analysis was used to test the agreement between methods. Among the four anthropometric equations, the Durnin-Womersley equation only showed close agreement with DXA in both female and male patients; the other equations significantly underestimated or overestimated %BF. Two new predictive equations were developed using DXA as the reference to predict total body and trunk %BF. Further comparative studies are required to confirm and refine the accuracy of practical, non-invasive methods for monitoring %BF in this population.

Obesity Impact Evaluated from Fat Percentage in Bone Mineral Density of Male Adolescents

OBJECTIVE

To analyze bone mineral density (BMD) values in adolescents and to assess obesity impact, measured through body fat #x2013;on this variable through the assessment by DEXA.

METHODOLOGY

A total of 318 males adolescents (12-17 years) were evaluated considering weight, height, body mass index (BMI), bone mineral density (BMD), fat and lean mass. BMD was assessed for the arms, legs, hips, and lumbar regions, as well as for total amount. Stratification of the nutritional status was determined by body fat (%BF) percentage; comparison of groups was scrutinized by analysis of variance; and the association of variables was performed using Pearson's test.

RESULTS

There was a progressive increase in weight, height, and BMD for all evaluated age groups following the advance of chronological age. A negative correlation was found between the %BF with BMD in all evaluated segments. Significant differences were found between the eutrophic group compared to the overweight group and the obesity group in the evaluated segments (P <0.01) noting a reduction of up to 12.92% for the lumbar region between eutrophic and obese.

CONCLUSION

The results suggest that increase %BF is associated with lower BMD among male adolescents.

Are the Recent Secular Increases in Waist Circumference among Children and Adolescents Independent of Changes in BMI?

Background

Several studies have shown that the waist circumference of children and adolescents has increased over the last 25 years. However, given the strong correlation between waist circumference and BMI, it is uncertain if the secular trends in waist circumference are independent of those in BMI.

Methods

We analyzed data from 6- to 19-year-olds who participated in the 1988–1994 through 2011–2012 cycles of the National Health and Nutrition Examination Survey to assess whether the trends in waist circumference were independent of changes in BMI, race-ethnicity and age.

Results

Mean, unadjusted levels of waist circumference increased by 3.7 cm (boys) and 6.0 cm (girls) from 1988–94 through 2011–12, while mean BMI levels increased by 1.1 kg/m² (boys) and 1.6 kg/m² (girls). Overall, the proportional changes in mean levels of both waist circumference and BMI were fairly similar among boys (5.3%, waist vs. 5.6%, BMI) and girls (8.7%, waist vs. 7.7%, BMI). As assessed by the area under the curve, adjustment for BMI reduced the secular increases in waist circumference by about 75% (boys) and 50% (girls) beyond that attributable to age and race-ethnicity. There was also a race-ethnicity interaction (p < 0.001). Adjustment for BMI reduced the secular trend in waist circumference among non-Hispanic (NH) black children (boys and girls) to a greater extent (about 90%) than among other children.

Conclusions

Our results indicate that among children in the U.S., about 75% (boys) and 50% (girls) of the secular increases in waist circumference since 1988–94 can be accounted for by changes in BMI. The reasons for the larger independent effects among girls and among NH blacks are uncertain.

Adherence to the Mediterranean diet is inversely associated with visceral abdominal tissue in Caucasian subjects

BACKGROUND

& aim: Adherence to the Mediterranean dietary pattern (MDP) is inversely related with abdominal adiposity as detected by waist circumference but the specific association to subcutaneous and visceral abdominal tissue has not been investigated. To this purpose we evaluated the association between MDP, visceral (VAT) and subcutaneous (SAT) abdominal tissue in a large sample of Italian adults.

METHODS

A cross-sectional study was carried out on 4388 consecutive adults (73.2% women) followed as outpatients at Nutritional Research Centre in Milan, ICANS. VAT and SAT were measured by ultrasonography. MDP was evaluated using a Mediterranean dietary score (MEDscore) obtained from a validated 14-item questionnaire.

RESULTS

At multiple linear regression adjusted for sex, age, smoking and physical activity, a 1-unit increase in MEDscore was associated with a -0.118 kg/m(2) decrease in BMI (p < 0.01), a -0.292 cm decrease in waist circumference (p < 0.01), a -0.002 cm:cm decrease in waist to height ratio (p < 0.001), a -1.125 mm decrease in the sum of 4 skinfolds (p < 0.001), and with a -0.045 cm decrease in VAT (p < 0.05). MEDscore was, however, not associated with SAT. Finally, the adherence to the MDP was a protective factor for obesity (OR = 0.717, 95%CI: 0.555-0.922) and VAT excess (OR = 0.717, 95%CI: 0.530-0.971).

CONCLUSION

Our study confirms the inverse association between MDP, BMI and waist circumference and adds that the association with abdominal obesity as detected by waist circumference is due to an association with VAT and not with SAT.

Childhood obesity affects adult metabolic syndrome and diabetes

We seek to observe the association between childhood obesity by different measures and adult obesity, metabolic syndrome (MetS), and diabetes. Thousand two hundred and nine subjects from "Beijing Blood Pressure Cohort Study" were followed 22.9 ± 0.5 years in average from childhood to adulthood. We defined childhood obesity using body mass index (BMI) or left subscapular skinfold (LSSF), and adult obesity as BMI ≥ 28 kg/m(2). MetS was defined according to the joint statement of International Diabetes Federation and American Heart Association with modified waist circumference (≥ 90/85 cm for men/women). Diabetes was defined as fasting plasma glucose ≥ 7.0 mmol/L or blood glucose 2 h after oral glucose tolerance test ≥ 11.1 mmol/L or currently using blood glucose-lowering agents. Multiple linear and logistic regression models were used to assess the association. The incidence of adult obesity was 13.4, 60.0, 48.3, and 65.1 % for children without obesity, having obesity by BMI only, by LSSF only, and by both, respectively. Compared to children without obesity, children obese by LSSF only or by both had higher risk of diabetes. After controlling for adult obesity, childhood obesity predicted independently long-term risks of diabetes (odds ratio 2.8, 95 % confidence interval 1.2-6.3) or abdominal obesity (2.7, 1.6-4.7) other than MetS as a whole (1.2, 0.6-2.4). Childhood obesity predicts long-term risk of adult diabetes, and the effect is independent of adult obesity. LSSF is better than BMI in predicting adult diabetes.

Are the recent secular increases in the waist circumference of adults independent of changes in BMI?

BACKGROUND

Several studies showed that the waist circumference of US adults has increased over the past 25 y. However, because of the high correlation between waist circumference and body mass index (BMI; in kg/m²) (r ∼ 0.9), it is uncertain if these trends in waist circumference exceed those expected on the basis of BMI changes over this time period.

OBJECTIVE

We assessed whether the recent trend in waist circumference was independent of changes in BMI, age, and race-ethnicity.

DESIGN

We analyzed data from the 1999-2000 through 2011-2012 cycles of the NHANES.

RESULTS

The mean waist circumference increased by ∼2 cm (in men) and ∼4 cm (in women) in adults in the United States over this 12-y period. In men, this increase was very close to what would be expected because of the 0.7 increase in mean BMI over this period. However, in women, most of the secular increase in waist circumference appeared to be independent of changes in BMI (mean: 0.6), age, and race-ethnicity over the 12-y period. We estimated that, independent of changes in these covariates, the mean waist circumference increased by 0.2 cm in men and 2.4 cm in women from 1999-2000 through 2011-2012; only the latter estimate was statistically significant.

CONCLUSIONS

Our results indicate that, in women but not men, the recent secular trend in waist circumference is greater than what would be expected on the basis of changes in BMI. Possible reasons for this secular increase, along with sex differences, are uncertain.