Adjustment For Changes In Body Mass Index Research Articles

Changes in Food and Nutrient Intake and Diet Quality on a Low-Fat Vegan Diet Are Associated with Changes in Body Weight, Body Composition, and Insulin Sensitivity in Overweight Adults: A Randomized Clinical Trial

BackgroundConsuming different food groups and nutrients can have differential effects on body weight, body composition, and insulin sensitivity. ObjectiveThe aim was to identify how food group, nutrient intake, and diet quality change relative to usual-diet controls after 16 weeks on a low-fat vegan diet and what associations those changes have with changes in body weight, body composition, and measures of metabolic health. DesignSecondary analysis of a randomized clinical trial conducted between October 2016 and December 2018 in four replications. Participants/settingParticipants included in this analysis were 219 healthy, community-based adults in the Washington, DC, area, with a body mass index (BMI) between 28 and 40, who were randomly assigned to either follow a low-fat vegan diet or make no diet changes. InterventionA low-fat, vegan diet deriving approximately 10% of energy from fat, with weekly classes including dietary instruction, group discussion, and education on the health effects of plant-based nutrition. Control group participants continued their usual diets. Main outcome measuresChanges in food group intake, macronutrient and micronutrient intake, and dietary quality as measured by Alternate Healthy Eating Index-2010 (AHEI-2010), analyzed from 3-day diet records, and associations with changes in body weight, body composition, and insulin sensitivity were assessed. Statistical analyses performedA repeated-measure analysis of variance model that included the factors group, subject, and time was used to test the between-group differences throughout the 16-week study. Interaction between group and time was calculated for each variable. Within each diet group, paired comparison t tests were calculated to identify significant changes from baseline to 16 weeks. Spearman correlations were calculated for the relationship between changes in food group intake, nutrient intake, AHEI-2010 score, and changes in body weight, body composition, and insulin sensitivity. The relative contribution of food groups and nutrients to weight loss was evaluated using linear regression. ResultsFruit, vegetable, legume, meat alternative, and whole grain intake significantly increased in the vegan group. Intake of meat, fish, and poultry; dairy products; eggs; nuts and seeds; and added fats decreased. Decreased weight was most associated with increased intake of legumes (r = −0.38; P < 0.0001) and decreased intake of total meat, fish, and poultry (r = +0.43; P < 0.0001). Those consuming a low-fat vegan diet also increased their intake of carbohydrates, fiber, and several micronutrients and decreased fat intake. Reduced fat intake was associated with reduced body weight (r = +0.15; P = 0.02) and, after adjustment for changes in BMI and energy intake, with reduced fat mass (r = +0.14; P = 0.04). The intervention group’s AHEI-2010 increased by 6.0 points on average, in contrast to no significant change in the control group (treatment effect, +7.2 [95% CI +3.7 to +10.7]; P < 0.001). Increase in AHEI-2010 correlated with reduction in body weight (r = 0.14; P = 0.04), fat mass (r = −0.14; P = 0.03), and insulin resistance as measured by the Homeostasis Model Assessment (HOMA-IR; r = −0.17; P = 0.02), after adjustment for changes in energy intake. ConclusionsWhen compared with participants’ usual diets, intake of plant foods increased, and consumption of animal foods, nuts and seeds, and added fats decreased on a low-fat vegan diet. Increased legume intake was the best single food group predictor of weight loss. Diet quality as measured by AHEI-2010 improved on the low-fat vegan diet, which was associated with improvements in weight and metabolic outcomes. These data suggest that increasing low-fat plant foods and minimizing high-fat and animal foods is associated with decreased body weight and fat loss, and that a low-fat vegan diet can improve measures of diet quality and metabolic health.

The association of parity/live birth number with incident type 2 diabetes among women: over 15\xa0years of follow-up in The Tehran Lipid and Glucose Study

BackgroundChildbearing may increase the future risk of developing type 2 diabetes mellitus (T2DM) in mothers. However, the issue is not clear completely and not investigated in the Middle East, a region with a high burden of T2DM. In the current study, we examined the association of parity/live birth number with incident T2DM among Iranian women.MethodsThe study population included 2552 women aged 30–65 years recruited in 1999–2001 and were followed for incident T2DM by 3-year intervals. Multivariable Cox proportional hazard models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the parity/live birth number for incident T2DM. Parity number was defined as the number of live childbirth (number of live birth) plus the number of stillbirth (defined as birth of an infant that died after the 20th week of pregnancy in the uterus).ResultsDuring a median follow-up of 15.4 years, 557 incident T2DM cases have occurred. After adjustment for potential T2DM risk factors and reproductive factors, each additional parity caused a 9% higher risk for incident T2DM. Moreover, compared to women with one parity, those with 3 and ≥ 4 parity had HRs of 1.73 [95% CI: 1.06–2.83] and 2.23 [1.36–3.65], respectively. After further adjustment for body mass index (BMI) and waist circumference, although the HRs were attenuated prominently, parity ≥ 4 was associated with significantly higher risk (HR: 1.72 [1.05–2.83]); even after further adjustment for triglycerides (TG)/ high-density lipoprotein cholesterol (HDL-C), the risk remained marginally significant (HR: 1.64 [1.00–2.70; P value: 0.051]). For the number of live birth, the results were also similar. Moreover, in a sensitivity analysis, when we considered BMI change during follow-up as another covariate, generally, the effect sizes did not change; the trend of HRs across categories of parity number remained marginally significant (P value: 0.064).ConclusionsDuring a long-term follow-up, after adjustment for potential T2DM risk factors, reproductive factors, obesity indices, and TG/HDL-C (insulin resistance surrogate), we demonstrated that higher parity/live birth numbers could be associated with increased risk of T2DM development among Iranian women. Moreover, even after further adjustment for BMI change, the suggestive higher risk was still found.

Associations of Visceral, Subcutaneous, Epicardial, and Liver Fat with Metabolic Disorders up to 14 Years After Weight Loss Surgery.

Background: Bariatric surgery leads to long-term remission and reduced incidence of diabetes, hypertension, and dyslipidemia. Short-term studies suggest reduction in specific fat depots may be more predictive of health improvement than reduced body mass index (BMI). Visceral, subcutaneous, epicardial, and liver fat, measured 11 years after bariatric surgery, were associated with long-term remission and incidence of diabetes, dyslipidemia, and hypertension. Methods: Fat depots an average of 11 (maximum 14) years after surgery were quantified by noncontrast computed tomography in subjects who did (N = 261; 86% gastric bypass) or did not (N = 243) have bariatric surgery. Multiple regression related fat depots to disease endpoints with and without adjustment for change in BMI and surgical status. Results: Visceral fat was 42% lower, subcutaneous fat 20% lower, epicardial fat 30% lower, and liver-to-spleen density ratio 9% higher at follow-up in the bariatric surgery group compared with the nonsurgery group (all P < 0.01). Higher visceral fat at follow-up exam was significantly associated with reduced remission and increased incidence of diabetes, hypertension, and dyslipidemia. Subcutaneous fat was not associated with disease. The liver-to-spleen ratio was associated with the remission and incidence of hypertriglyceridemia and not with other fat depots. Epicardial fat was related to incidence of elevated low-density lipoprotein cholesterol and low high-density lipoprotein cholesterol. Conclusions: Whether or not a patient shows greater long-term diabetes, dyslipidemia, or hypertension remission or incidence after bariatric surgery appears dependent on the amount of fat within specific fat depots measured at follow-up. Furthermore, associations of the three disease endpoints with different fat depots suggest varied fat depot pathology.

A Plant-Based Diet Improves Beta-Cell Function and Insulin Resistance in Overweight Adult—A 16-Week Randomized Clinical Trial

Background: The aim of this study was to test the effect of a 16-week plant-based dietary intervention on beta-cell function and insulin resistance in overweight adults with no history of diabetes. Methods: Participants (n=75) were randomized to follow a low-fat vegan diet (n=38) or to make no diet changes (n=37) for 16 weeks. At baseline and 16 weeks, beta-cell function was assessed during standard meal tests. Insulin secretory rate was calculated by C-peptide deconvolution, and beta-cell function was quantified with a mathematical model. HOMA-IR (The Homeostasis Model Assessment) index was used to assess insulin resistance while fasting. Repeated measure ANOVA was used for statistical analysis. Results: A marked increase in glucose-stimulated insulin secretion was observed in the intervention group compared with controls (interaction between group and time, Gxt, p&amp;lt;0.001). HOMA-IR index fell significantly (p&amp;lt;0.001) in the intervention group (treatment effect -1.0 [95% CI, -1.2 to -0.8]; Gxt, p=0.004). Changes in HOMA-IR correlated positively with changes in body mass index (BMI) and visceral fat volume (r=0.34; p=0.009 and r=0.42; p=0.001, respectively). The latter remained significant after adjustment for changes in BMI (r=0.41; p=0.002). Changes in glucose-induced insulin secretion correlated negatively with BMI changes (r=-0.25; p=0.04), but not with changes in visceral fat. Conclusions: A 16-week low-fat vegan dietary intervention improved beta-cell function and insulin resistance in overweight adults. The improvement in insulin resistance was related to loss of visceral fat, independent of changes in BMI. Disclosure H. Kahleova: None. A. Tura: None. M. Hill: None. R. Holubkov: Other Relationship; Self; Pfizer Inc., MedImmune. N. Barnard: None.

Body mass index throughout adulthood, physical activity, and risk of multiple myeloma: a prospective analysis in three large cohorts

BackgroundObesity is the only known modifiable multiple myeloma (MM) risk factor. However, the influence of obesity in earlier or later adulthood and the role of other energy balance correlates in MM development are unclear.MethodsWe leveraged repeatedly updated data from the Nurses’ Health Study, Health Professionals Follow-up Study, and Women’s Health Study cohorts to further explore energy balance measures in MM etiology. Exposures derived from questionnaires included young adult body mass index (BMI), cumulative average BMI, BMI change since young adulthood, and cumulative average physical activity and walking. We assessed MM risk related to those variables with Cox proportional hazard models.ResultsWe observed 575 incident MM cases in over five million person-years of follow-up across the cohorts. In pooled analyses, MM risk increased 17% per 5 kg/m2 increase in cumulative average BMI (95% confidence interval (CI): 1.05, 1.29) and 28% per 5 kg/m2 increase in young adult BMI (CI: 1.12, 1.47); adjustment for BMI change since young adulthood did not affect either association. BMI change since young adulthood and cumulative average physical activity and walking were not significantly associated with MM risk.ConclusionsThese findings suggest that a high BMI in early and later adulthood are risk factors for MM.

A Plant-Based Dietary Intervention Improves Beta-Cell Function and Insulin Resistance in Overweight Adults: A 16-Week Randomized Clinical Trial.

The aim of this study was to test the effect of a plant-based dietary intervention on beta-cell function in overweight adults with no history of diabetes. Participants (n = 75) were randomized to follow a low-fat plant-based diet (n = 38) or to make no diet changes (n = 37) for 16 weeks. At baseline and 16 weeks, beta-cell function was quantified with a mathematical model. Using a standard meal test, insulin secretory rate was calculated by C-peptide deconvolution. The Homeostasis Model Assessment (HOMA-IR) index was used to assess insulin resistance while fasting. A marked increase in meal-stimulated insulin secretion was observed in the intervention group compared with controls (interaction between group and time, Gxt, p < 0.001). HOMA-IR index fell significantly (p < 0.001) in the intervention group (treatment effect −1.0 (95% CI, −1.2 to −0.8); Gxt, p = 0.004). Changes in HOMA-IR correlated positively with changes in body mass index (BMI) and visceral fat volume (r = 0.34; p = 0.009 and r = 0.42; p = 0.001, respectively). The latter remained significant after adjustment for changes in BMI (r = 0.41; p = 0.002). Changes in glucose-induced insulin secretion correlated negatively with BMI changes (r = −0.25; p = 0.04), but not with changes in visceral fat. Beta-cell function and insulin sensitivity were significantly improved through a low-fat plant-based diet in overweight adults.

The effect of change in body mass index on volumetric measures of mammographic density.

Understanding how changes in body mass index (BMI) relate to changes in mammographic density is necessary to evaluate adjustment for BMI gain/loss in studies of change in density and breast cancer risk. Increase in BMI has been associated with a decrease in percent density, but the effect on change in absolute dense area or volume is unclear. We examined the association between change in BMI and change in volumetric breast density among 24,556 women in the San Francisco Mammography Registry from 2007 to 2013. Height and weight were self-reported at the time of mammography. Breast density was assessed using single x-ray absorptiometry measurements. Cross-sectional and longitudinal associations between BMI and dense volume (DV), non-dense volume (NDV), and percent dense volume (PDV) were assessed using multivariable linear regression models, adjusted for demographics, risk factors, and reproductive history. In cross-sectional analysis, BMI was positively associated with DV [β, 2.95 cm(3); 95% confidence interval (CI), 2.69-3.21] and inversely associated with PDV (β, -2.03%; 95% CI, -2.09, -1.98). In contrast, increasing BMI was longitudinally associated with a decrease in both DV (β, -1.01 cm(3); 95% CI, -1.59, -0.42) and PDV (β, -1.17%; 95% CI, -1.31, -1.04). These findings were consistent for both pre- and postmenopausal women. Our findings support an inverse association between change in BMI and change in PDV. The association between increasing BMI and decreasing DV requires confirmation. Longitudinal studies of PDV and breast cancer risk, or those using PDV as an indicator of breast cancer risk, should evaluate adjustment for change in BMI.

Independent effects of age-related changes in waist circumference and BMI z scores in predicting cardiovascular disease risk factors in a prospective cohort of adolescent females

Cross-sectional data indicate that central adiposity is associated with cardiovascular disease risk, independent of total adiposity. The use of longitudinal data to investigate the relation between changes in fat distribution and the emergence of risk factors is limited. We tested the hypothesis that age-related change in waist circumference (to reflect central adiposity) during adolescence is a significant predictor of longitudinal change in cardiovascular disease risk, after adjustment for change in body mass index (BMI) z score (to reflect total adiposity) in a cohort of postmenarcheal adolescent females. We also tested whether race modified this relation. We analyzed publicly available data from the National Heart, Lung, and Blood Institute Growth and Health Study. Longitudinal regression models were fitted to investigate the independent effects of changes in waist circumference on cardiovascular disease risk factors. Steeper age-related increases in waist circumference over time were associated with a greater increase in LDL-cholesterol concentrations, systolic blood pressure, diastolic blood pressure, and homeostasis model assessment of insulin resistance, after adjustment for BMI z score, in white but not in black females. Change in waist circumference was not a statistically significant predictor of age-related changes in HDL-cholesterol, triglyceride, insulin, and glucose concentrations, after adjustment for changes in BMI z score, in either white or black females. Our research suggests that monitoring waist circumference in addition to BMI z score has the potential to identify adolescents at risk of the emergence of cardiovascular disease risk factors, at least in white females. The data also suggest that race may modify the relation between fat distribution pattern and cardiovascular disease risk factors.

Association of Lactate With Blood Pressure Before and After Rapid Weight Loss

The mechanism linking obesity with its downstream complications is poorly understood. Accumulating evidence suggests that insufficient oxidative capacity plays a central role in the development of insulin resistance and, perhaps, hypertension. To investigate this hypothesis, we measured lactate, a marker of the gap between energy expenditure and oxidative capacity, in 40 obese subjects with the metabolic syndrome (Ob-MS), 40 obese subjects without the metabolic syndrome (Ob), and 20 lean controls (LCs). The 40 Ob-MS participants were then entered into a 12-20 week very low-calorie diet (VLCD) intervention. The change in lactate and a number of other metabolic factors including blood pressure were subsequently assessed. At baseline, median lactate levels were significantly higher in both the Ob (36.4 mg/dl) and Ob-MS (34.7 mg/dl) groups when compared to LCs (17.4 mg/dl; P < 0.001). After the VLCD intervention, Ob-MS subjects lost 14.7 kg on average, corresponding to a 5.0 kg/m(2) decrease in body mass index (BMI). Lactate levels fell from 41.3 to 28.7 mg/dl, a 31% reduction (P = 0.006). Even after adjustment for BMI change, change in lactate was strongly associated with change in diastolic blood pressure (DBP) (P = 0.007) and mean arterial pressure (P = 0.014), but not with systolic blood pressure (SBP) (P = 0.20) or other obesity-related traits. Baseline and longitudinal associations between lactate and DBP suggest that insufficient oxidative capacity may play a role in obesity-related hypertension.

Adiponectin, an adipocyte-derived protein, predicts future insulin resistance: two-year follow-up study in Japanese population.

It has been reported that the serum adiponectin level was negatively correlated with body mass index (BMI), insulin resistance index, and triglycerides and was positively correlated with high-density lipoprotein cholesterol in several cross-sectional studies. However, the causal relationship has not been elucidated. We investigated whether the baseline adiponectin level could predict subsequent changes in insulin resistance, lipid profile, or body weight in a 2-yr longitudinal study. This study included 590 male Japanese subjects, aged 30-65 yr, who received annual health checkups in both 2000 and 2002. Blood pressure, heart rate, and anthropometric and metabolic parameters, including serum insulin and adiponectin levels, were determined. The insulin resistance index was calculated based on homeostasis model assessment. Baseline adiponectin level was not correlated with the subsequent change in lipid profile or BMI in 2 yr after adjustment for each baseline value. However, the baseline adiponectin level was negatively correlated with subsequent changes in insulin and insulin resistance index based on homeostasis model assessment, even after adjustment for change in BMI (r = -0.162 and r = -0.140, respectively). These findings suggest that the serum adiponectin concentration predicts subsequent changes in insulin resistance, but not in lipid profile or body weight.

Relative hypoleptinaemia in women with mild gestational diabetes mellitus.

There is increasing evidence suggesting that leptin plays a major role in the regulation of energy homeostasis, as well as in the neuroendocrine and reproductive systems. Leptin is synthesized in the human placenta. The aim of this study was to relate serum leptin levels during pregnancy to glucose tolerance, body mass index (BMI) and specific metabolic variables, such as specific insulin and proinsulin. A 2-h 75 g oral glucose tolerance test was performed in 221 pregnant women at 22-29 weeks of gestation (median 25th week). Serum leptin was measured using a radioimmunoassay. In 49 women, sequential leptin measurements were performed (during pregnancy and post partum (median 5 months)). During pregnancy serum leptin was significantly related to body weight (r = 0.49), BMI (r = 0.51), fasting immunoreactive insulin (r = 0.46), specific insulin (r = 0.43) and proinsulin (r = 0.29) (all P-values <0.0001). In women with mild gestational diabetes (GDM, n = 55), leptin levels were lower compared to women with normal glucose tolerance (n = 166) after adjusting for BMI and fasting insulin (26.9 vs. 19.4 ng/ml, P = 0.0001). Leptin was significantly higher during pregnancy compared to post partum (mean +/- SE: 24.3+/-1.5 vs. 19.6+/-1.6 ng/ml, P = 0.0003), even after adjustment for changes in BMI and changes in fasting insulin (P = 0.013). Leptin levels are elevated in pregnancy. Women with mild GDM presented with relative hypoleptinaemia compared to women with normal glucose tolerance.