Fitness and Fatness: Body Mass Index versus Percent Body Fat

2019 ◽  
Vol 8 (4) ◽  
pp. 131-137
Author(s):  
Jennifer Bunn ◽  
Danielle Eustace ◽  
Taylor Miskech ◽  
John Manor ◽  
Michael Jiroutek

ABSTRACT Background: Body mass index (BMI) is frequently used to evaluate risk of disease, but can be misleading because it does not account for different types of tissue mass (e.g., bone, muscle, fat). The purpose of this study was to classify adults in the United States according to cardiovascular fitness (CVF), BMI, and body fat using the National Health and Nutrition Examination Survey (NHANES) data. Methods: The three most current NHANES datasets (6,648 records) were included. Counts, means, and 95% confidence intervals (CI) determined the distribution of CVF across percent of body fat and BMI categories. Results: According to BMI, approximately 42.3% of participants were classified as either underweight or normal weight, and 24.9% were classified as obese. According to percent of body fat, 13.5% of subjects were classified as lean, while 68.4% of subjects were in the high percent body fat group. In regard to BMI, 9.9% and 6.7% of the overweight and obese populations, respectively, were classified in the highest third of CVF. According to adiposity, 6.6% and 21.0% of the moderate and high percent body fat population fell into the same category, respectively. Conclusion: Two-thirds of the population ranked below the 35th percentile for body fat (high percent body fat), with more of these individuals in the low CVF category than any other. The largest categorization for BMI was the normal-weight category. This supports that BMI may be misleading, and that utilizing percent body fat and CVF may provide a better indication of health.

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Joan A. Vaccaro ◽  
Fatma G. Huffman

Background. Approximately 17% of children aged 6–11 years were classified as obese in the United States. Obesity adversely affects physical functioning and leads to reduced quality of life. Heart function for overweight and obese children has not been reported.Methods. Data for this study were from NHANES National Youth Fitness Survey (NNYFS) conducted in conjunction with the National Health and Nutrition Examination Survey (NHANES) in 2012. This study used data from children aged 6–12 (N=732) that had the cardiorespiratory endurance measure, body mass index for age and sex, and dietary data (N=682). Cardiovascular endurance was estimated by heart rate reserve.Results. Compared to the highest percentile of heart rate reserve, those in the first percentile had 3.52 (2.36, 5.24) odds and those in the second percentile had 3.61 (1.84, 7.06) odds of being in the overweight/obese as compared to the under/normal weight category. Considering the highest percentile, boys had a heart rate reserve of 35%, whereas girls had a heart rate reserve of 13% (less than half that of boys).Conclusion. Having an overweight or obese classification for children in this study demonstrated a compromise in cardiovascular endurance. Parental awareness should be raised as to the detrimental consequence of overweight and heart health.


BMJ ◽  
2021 ◽  
pp. n365
Author(s):  
Buyun Liu ◽  
Yang Du ◽  
Yuxiao Wu ◽  
Linda G Snetselaar ◽  
Robert B Wallace ◽  
...  

AbstractObjectiveTo examine the trends in obesity and adiposity measures, including body mass index, waist circumference, body fat percentage, and lean mass, by race or ethnicity among adults in the United States from 2011 to 2018.DesignPopulation based study.SettingNational Health and Nutrition Examination Survey (NHANES), 2011-18.ParticipantsA nationally representative sample of US adults aged 20 years or older.Main outcome measuresWeight, height, and waist circumference among adults aged 20 years or older were measured by trained technicians using standardized protocols. Obesity was defined as body mass index of 30 or higher for non-Asians and 27.5 or higher for Asians. Abdominal obesity was defined as a waist circumference of 102 cm or larger for men and 88 cm or larger for women. Body fat percentage and lean mass were measured among adults aged 20-59 years by using dual energy x ray absorptiometry.ResultsThis study included 21 399 adults from NHANES 2011-18. Body mass index was measured for 21 093 adults, waist circumference for 20 080 adults, and body fat percentage for 10 864 adults. For the overall population, age adjusted prevalence of general obesity increased from 35.4% (95% confidence interval 32.5% to 38.3%) in 2011-12 to 43.4% (39.8% to 47.0%) in 2017-18 (P for trend<0.001), and age adjusted prevalence of abdominal obesity increased from 54.5% (51.2% to 57.8%) in 2011-12 to 59.1% (55.6% to 62.7%) in 2017-18 (P for trend=0.02). Age adjusted mean body mass index increased from 28.7 (28.2 to 29.1) in 2011-12 to 29.8 (29.2 to 30.4) in 2017-18 (P for trend=0.001), and age adjusted mean waist circumference increased from 98.4 cm (97.4 to 99.5 cm) in 2011-12 to 100.5 cm (98.9 to 102.1 cm) in 2017-18 (P for trend=0.01). Significant increases were observed in body mass index and waist circumference among the Hispanic, non-Hispanic white, and non-Hispanic Asian groups (all P for trend<0.05), but not for the non-Hispanic black group. For body fat percentage, a significant increase was observed among non-Hispanic Asians (30.6%, 29.8% to 31.4% in 2011-12; 32.7%, 32.0% to 33.4% in 2017-18; P for trend=0.001), but not among other racial or ethnic groups. The age adjusted mean lean mass decreased in the non-Hispanic black group and increased in the non-Hispanic Asian group, but no statistically significant changes were found in other racial or ethnic groups.ConclusionsAmong US adults, an increasing trend was found in obesity and adiposity measures from 2011 to 2018, although disparities exist among racial or ethnic groups.


2021 ◽  
pp. 089011712110291
Author(s):  
Puneet Kaur Chehal ◽  
Livvy Shafer ◽  
Solveig Argeseanu Cunningham

Purpose: This study contributes to the growing literature on the association between sleep and obesity by examining the associations between hours of sleep, consistency of bedtime, and obesity among children in the US. Design: Analysis of a nationally representative sample of non-institutionalized children from the 2016-17 National Survey of Children’s Health. Setting: US, national. Subjects: Children ages 10-17 years (n = 34,640) Measures: Parent reported weeknight average hours of sleep and consistency of bedtime. Body mass index classified as underweight, normal, overweight or obesity using parent-reported child height and weight information, classified using CDC BMI-for-Age Growth Charts. Analysis: Multivariate logistic regression models were used to estimate associations between measures of sleep and body mass index weight category adjusting for individual, household and neighborhood characteristics. Results: An additional hour of sleep was associated with 10.8% lower odds of obesity, net of consistency in bedtime. After controlling for sleep duration, children who usually went to bed at the same time on weeknights had lower odds of obesity (24.8%) relative to children who always went to bed at the same time. Conclusion: Sleep duration is predictive of lower odds of obesity in US children and adolescents. Some variability in weeknight bedtime is associated with lower odds of obesity, though there were no additional benefits to extensive variability in bedtime.


2016 ◽  
Vol 41 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Alexandra P Frost ◽  
Tracy Norman Giest ◽  
Allison A Ruta ◽  
Teresa K Snow ◽  
Mindy Millard-Stafford

Background: Body composition is important for health screening, but appropriate methods for unilateral lower extremity amputees have not been validated. Objectives: To compare body mass index adjusted using Amputee Coalition equations (body mass index–Amputee Coalition) to dual-energy X-ray absorptiometry in unilateral lower limb amputees. Study design: Cross-sectional, experimental. Methods: Thirty-eight men and women with lower limb amputations (transfemoral, transtibial, hip disarticulation, Symes) participated. Body mass index (mass/height2) was compared to body mass index corrected for limb loss (body mass index–Amputee Coalition). Accuracy of classification and extrapolation of percent body fat with body mass index was compared to dual-energy X-ray absorptiometry. Results: Body mass index–Amputee Coalition increased body mass index (by ~ 1.1 kg/m2) but underestimated and mis-classified 60% of obese and overestimated 100% of lean individuals according to dual-energy X-ray absorptiometry. Estimated mean percent body fat (95% confidence interval) from body mass index–Amputee Coalition (28.3% (24.9%, 31.7%)) was similar to dual-energy X-ray absorptiometry percent body fat (29.5% (25.2%, 33.7%)) but both were significantly higher ( p < 0.05) than percent body fat estimated from uncorrected body mass index (23.6% (20.4%, 26.8%)). However, total errors for body mass index and body mass index–Amputee Coalition converted to percent body fat were unacceptably large (standard error of the estimate = 6.8%, 6.2% body fat) and the discrepancy between both methods and dual-energy X-ray absorptiometry was inversely related ( r = −0.59 and r = −0.66, p < 0.05) to the individual’s level of body fatness. Conclusions: Body mass index (despite correction) underestimates health risk for obese patients and overestimates lean, muscular individuals with lower limb amputation. Clinical relevance Clinical recommendations for an ideal body mass based on body mass index–Amputee Coalition should not be relied upon in lower extremity amputees. This is of particular concern for obese lower extremity amputees whose health risk might be significantly underestimated based on body mass index despite a “correction” formula for limb loss.


2019 ◽  
Vol 13 (1) ◽  
pp. 570-575 ◽  
Author(s):  
Hosein Sheibani ◽  
Habibollah Esmaeili ◽  
Maryam Tayefi ◽  
Maryam Saberi-Karimian ◽  
Susan Darroudi ◽  
...  

2018 ◽  
Vol 26 (3) ◽  
pp. 230949901880242 ◽  
Author(s):  
Usha Gurunathan ◽  
Aaron Pym ◽  
Cameron Anderson ◽  
Amanda Marshall ◽  
Sarah L Whitehouse ◽  
...  

Purpose: To investigate the association between body mass index (BMI) and perioperative complications until hospital discharge, following primary total knee arthroplasty (TKA). Methods: This retrospective study reviewed 1665 cases of elective primary unilateral TKA performed between 2006 and 2010, from a prospective secure electronic database. Types of complications, length of operating time, and duration of hospital stay were analyzed in both adjusted (for known confounders) and unadjusted analyses. A further matched analysis was also performed. Results: In terms of overall complications, there was no statistically significant difference between the BMI categories. When individual obesity category was considered, obese 2 had the lowest odds of developing complications, both with unadjusted (odds ratio (OR): 0.61, 95% confidence interval (CI) 0.41–0.91, p < 0.015) and adjusted regression analysis (OR: 0.65, 95% CI: 0.43–0.99, p = 0.044). Compared to normal weight category, obese class 3 (≥40 kg/m2) individuals were at 66% (OR: 0.34, 95% CI: 0.21–0.55) lower (unadjusted) odds of developing cardiac complications (overall p < 0.001). With the matched analysis, compared to normal weight category, obese class 3 (≥40 kg/m2) individuals were at a 60% (OR: 0.40, 95% CI: 0.23–0.68) lower (unadjusted) odds of developing cardiac complications (overall p = 0.004). Obese 3 patients had significantly higher operating time compared with other groups ( p < 0.001). Conclusion: This study did not find a significant association between BMI and increased overall in-hospital medical or surgical complications following primary TKA. Obesity significantly increased the length of operating time.


1998 ◽  
Vol 76 (2) ◽  
pp. 237-241 ◽  
Author(s):  
L J Martin ◽  
PJH Jones ◽  
R V Considine ◽  
W Su ◽  
N F Boyd ◽  
...  

To investigate whether circulating leptin levels are associated with energy expenditure in healthy humans, doubly labeled water energy measurements and food intake assessment were carried out in 27 women (mean age, 48.6 years; weight, 61.9 kg; body mass index, 23.2). Energy expenditure was determined over 13 days. Food intake was measured by 7-day food records. Leptin was measured by radioimmunoassay. Leptin level was strongly associated with percentage body fat (r = 0.59; p < 0.001), fat mass (r = 0.60; p < 0.001), and body mass index (r = 0.41; p = 0.03), but no correlation was observed with energy expenditure (r = 0.02; p = 0.93). After controlling for percentage body fat, a positive association of leptin level with energy expenditure of marginal significance (p = 0.06) was observed. There were no significant univariate associations of age, physical activity, lean body mass, height, or dietary variables with leptin level. When controlling for body fat, a significant positive correlation was observed for percent energy from carbohydrate and negative correlations with dietary fat and alcohol intake. These findings confirm previous associations between leptin and body fat content and suggest a relationship between serum leptin and energy expenditure level in healthy humans.Key words: leptin, energy expenditure, body composition, diet.


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