Standard Body Mass Index Categories Research Articles

Influence of Body Mass Index on Effects of a Shared Asthma Treatment Decision-Making Intervention

Asthma is a significant public health problem, with approximately 24.6 million Americans reporting current asthma in 2009 (1). Obesity prevalence has continuously increased over the last 30 years, reaching 33.8% among U.S. adults in 2007–2008 (2). A meta-analysis of prospective studies showed a dose-dependent relationship between increasing body mass index (BMI) and the risk of incident asthma (3). Understanding the influence of BMI and obesity on effectiveness of interventions to improve asthma control will help clinicians better care for obese patients with asthma. The Better Outcomes of Asthma Treatment study, a randomized controlled trial in 612 adults with poorly controlled asthma, found that a shared treatment decision-making (SDM) intervention improved controller medication adherence and clinical outcomes (4). Given the increased attention to the links between obesity and asthma, we conducted post hoc analyses to investigate whether baseline BMI modified the SDM intervention effects on asthma medication acquisition outcomes (fill/refill adherence and regimen strength) and clinical outcomes in the follow-up year. We hypothesized that obese patients would have benefitted less from the SDM intervention than did overweight or normal weight patients. Some of the results reported here were previously reported in the form of an abstract (5). Standard BMI categories were defined: normal (18.5–24.9 kg/m2, n = 132) and underweight (< 18.5 kg/m2, n = 7) combined, overweight (25–29.9 kg/m2, n = 185), and obese (≥ 30 kg/m2, n = 286).Using comprehensive pharmacy dispensing records, we computed continuous medication acquisition (CMA) indices (6–8) to measure fill/refill adherence for controller medications (inhaled corticosteroids, leukotriene modifiers, and others) and for long-acting β agonists (LABA) during the 12 months before and after randomization of individual participants. Controller and LABA medication regimen strength was measured by cumulative beclomethasone canister-equivalents (C-E) and salmeterol diskus-equivalents (D-E), respectively, using a standardized weighting methodology (9). Clinical outcome measures included the symptom subscale of the Juniper mini-Asthma Quality of Life Questionnaire (mini-AQLQ) (10), the Asthma Therapy Assessment Questionnaire (ATAQ) (11), asthma-related health care utilization, rescue medication use (via albuterol C-E), and lung function. Multivariable regression models were used to determine whether BMI modified the SDM intervention effect on these outcomes relative to usual care. Compared with the controller regimen strength among normal weight SDM patients (0.036 ± 0.02 C-E), obese (0.05 ± 0.026 C-E, P = 0.027) and overweight SDM patients (0.048 ± 0.03 C-E, P = 0.0007) negotiated a higher daily controller dose. BMI negatively modified the SDM intervention effect on controller fill/refill adherence (P = 0.04; Figure 1). The SDM-related increase in controller CMA index among obese patients, relative to obese usual care patients, was smaller than observed for the other weight groups, although still in a favorable direction (β = 0.086; 95% confidence interval [CI], −0.03 to 0.202; P = 0.15). Obese SDM patients also received a smaller intervention benefit (but still significantly better than UC) in terms of the total number of salmeterol D-E dispensed (β = 1.82; 95% CI, 0.81 to 2.84; P = 0.0005) than SDM patients in other weight groups (interaction term P = 0.04). Figure 1. Increase in controller continuous medication acquisition (CMA) associated with shared decision-making (SDM) intervention, compared with usual care, by body mass index (BMI) category. *Normal weight: n = 139; β-coefficient for SDM versus UC: P ... BMI did not significantly modify the observed beneficial SDM intervention effects on any of the clinical outcomes. Like normal weight and overweight SDM patients, obese SDM patients demonstrated significantly better clinical outcomes compared with obese patients in usual care for asthma-related health care utilization, use of rescue medication (albuterol C-E), the FEV1 and FEV1/FEV6 ratio, and the odds of reporting no asthma control problems (a score of 0) on the ATAQ scale. Although these analyses are exploratory, and thus, further research is needed, these results demonstrate that a shared decision-making approach to treatment choice can clinically benefit adult patients with poorly controlled asthma, regardless of BMI.

Validity of self‐reported height and weight and derived body mass index in middle‐aged and elderly individuals in Australia

Body mass index (BMI) is an important measure of adiposity. While BMI derived from self-reported data generally agrees well with that derived from measured values, evidence from Australia is limited, particularly for the elderly. We compared self-reported with measured height and weight in a random sample of 608 individuals aged ≥ 45 from the 45 and Up Study, an Australian population-based cohort study. We assessed degree of agreement and correlation between measures, and calculated sensitivity and specificity to quantify BMI category misclassification. On average, in males and females respectively, height was overestimated by 1.24 cm (95% CI: 0.75-1.72) and 0.59 cm (0.26-0.92); weight was underestimated by 1.68 kg (-1.99- -1.36) and 1.02 kg (-1.24- -0.80); and BMI based on self-reported measures was underestimated by 0.90 kg/m2 (-1.09- -0.70) and 0.60 kg/m2 (-0.75- -0.45). Underestimation increased with increasing measured BMI. There were strong correlations between self-reported and measured height, weight and BMI (r=0.95, 0.99 and 0.95, respectively, p<0.001). While there was excellent agreement between BMI categories from self-reported and measured data (kappa=0.80), obesity prevalence was underestimated. Findings did not differ substantially between middle-aged and elderly participants. Self-reported data on height and weight quantify body size appropriately in middle-aged and elderly individuals for relative measures, such as quantiles of BMI. However, caution is necessary when reporting on absolute BMI and standard BMI categories, based on self-reported data, particularly since use of such data is likely to result in underestimation of the prevalence of obesity.

Obesity and mammography: a systematic review and meta-analysis.

BACKGROUNDObese women experience higher postmenopausal breast cancer risk, morbidity, and mortality and may be less likely to undergo mammography.OBJECTIVESTo quantify the relationship between body weight and mammography in white and black women.DATA SOURCES AND REVIEW METHODSWe identified original articles evaluating the relationship between weight and mammography in the United States through electronic and manual searching using terms for breast cancer screening, breast cancer, and body weight. We excluded studies in special populations (e.g., HIV-positive patients) or not written in English. Citations and abstracts were reviewed independently. We abstracted data sequentially and quality information independently.RESULTSOf 5,047 citations, we included 17 studies in our systematic review. Sixteen studies used self-reported body mass index (BMI) and excluded women <40 years of age. Using random-effects models for the six nationally representative studies using standard BMI categories, the combined odds ratios (95% CI) for mammography in the past 2 years were 1.01 (0.95 to 1.08), 0.93 (0.83 to 1.05), 0.90 (0.78 to 1.04), and 0.79 (0.68 to 0.92) for overweight (25–29.9 kg/m2), class I (30–34.9 kg/m2), class II (35–39.9 kg/m2), and class III (≥40 kg/m2) obese women, respectively, compared to normal-weight women. Results were consistent when all available studies were included. The inverse association was found in white, but not black, women in the three studies with results stratified by race.CONCLUSIONSMorbidly obese women are significantly less likely to report recent mammography. This relationship appears stronger in white women. Lower screening rates may partly explain the higher breast cancer mortality in morbidly obese women.

Resultados obstétricos asociados al incremento del índice de masa corporal durante el embarazo en el Hospital Clínico de la Universidad de Chile

BackgroundPrevious studies have shown that an increase in body mass index (BMI) is associated with a greater risk of obstetric complications. AimTo investigate the effect of an increase in BMI category on obstetric outcomes in Hospital Clínic of the University of Chile. Material and methodsA retrospective study was conducted of women followed-up in the hospital from 2001 to 2006. Women with singleton pregnancies were placed in standard BMI categories. Increases in BMI were calculated as the difference between initial BMI and that at delivery. Fisher's exact test was used to compare categorical variables and the t test between two means was used for continuous variables. ResultsThis study included 5,478 women: 568 (10.48%) had no change in BMI category and 4.910 (89.51%) increased their BMI by ≥ 1 category. An increase in BMI category was associated with higher rates of preeclampsia (p=0.004) and cesarean delivery (p=0.009) in overweight women but not in women with a healthy weight at the beginning of pregnancy. Obese women had a higher risk of preeclampsia (p=0.008), gestational diabetes (p<0.001), cesarean delivery (p<0.001), and postpartum infection (p=0.009). ConclusionsAn increase in BMI category is associated with a greater risk of obstetric complications.

Obstetric outcomes associated with increase in BMI category during pregnancy

The purpose of this study was to investigate effect of increase in body mass index (BMI) category on obstetric outcomes. A cohort study was conducted from 1999 to 2002. Women with singleton pregnancies were placed in standard BMI categories. Increase in BMI was calculated as difference between initial BMI and delivery BMI. ANOVA was used to compare continuous variables, and chi-square test for categorical variables. This study included 5131 women: 49.8% had no change in BMI category, 43.9% increased by 1 BMI category, and 6.3% by >1 category. Increase in BMI category was associated with higher rates of gestational diabetes (P = .005), failed induction (P < .001), lacerations (P < .001), cesarean deliveries (P < .001), and postpartum infection (P = .007) in normal weight women. Overweight women also had increased rates of preeclampsia (P = .002) and operative vaginal deliveries (P < .001). Obese women had higher rates of chorioamnionitis (P = .003), failed induction (P < .001), and cesarean deliveries (P = .016). Increase in BMI category is associated with increased risk of complications.