Miryoung Lee

Anatomical Patterning of Visceral Adipose Tissue: Race, Sex, and Age Variation

Objective: We tested sex, race, and age differences in the patterning of visceral adipose tissue (VAT) and subcutaneous adipose tissue.

Inverse association between adiposity and telomere length: The fels longitudinal study

To assess the relationship between telomere length and adiposity, using dual‐energy X‐ray absorptiometry (DXA) and magnetic resonance imaging (MRI), in addition to conventional anthropometric proxies including body mass index (BMI) and cardiovascular disease risk factors.

Body Composition Methods: Comparisons and Interpretation

The incidence of obesity in the United States and other developed countries is epidemic. Because the prevalence of comorbidities to obesity, such as type 2 diabetes, has also increased, it is clear there is a great need to monitor and treat obesity and its comorbidities. Body composition assessments vary in precision and in the target tissue of interest. The most common assessments are anthropometric and include weight, stature, abdominal circumference, and skinfold measurements. More complex methods include bioelectrical impedance, dual-energy X-ray absorptiometry, body density, and total body water estimates. There is no single universally recommended method for body composition assessment in the obese, but each modality has benefits and drawbacks. We present here the most common methods and provide guidelines by way of examples to assist the clinician/researcher in choosing methods appropriate to their situation.

Rapid Postnatal Weight Gain and Visceral Adiposity in Adulthood: The Fels Longitudinal Study

Rapid infant weight gain is associated with increased abdominal adiposity, but there is no published report of the relationship of early infant growth to differences in specific adipose tissue depots in the abdomen, including visceral adipose tissue (VAT). In this study, we tested the associations of birth weight, infant weight gain, and other early life traits with VAT, abdominal subcutaneous adipose tissue (ASAT), and other body composition measures using magnetic resonance imaging (MRI) and dual‐energy X‐ray absorptiometry in middle adulthood (mean age = 46.5 years). The sample included 233 appropriate for gestational age singleton white children (114 males) enrolled in the Fels Longitudinal Study. Multivariate‐adjusted general linear models were used to test the association of infant weight gain (from 0 to 2 years), maternal BMI, gestational age, parity, maternal age, and other covariates with adulthood body composition. Compared to infants with slow weight gain, rapid weight gain was associated with elevated risk of obesity (adjusted odds ratio = 4.1, 95% confidence interval = 1.4, 11.1), higher total body fat (+7 kg, P = 0.0002), percent body fat (+5%, P = 0.0006), logVAT mass (+0.43 kg, P = 0.02), logASAT mass (+0.47 kg, P = 0.001), and percent abdominal fat (+5%, P = 0.03). There was no evidence that the increased abdominal adipose tissue was due to a preferential deposition of VAT. In conclusion, rapid infant weight gain is associated with increases in both VAT and ASAT, as well as total adiposity and the risk of obesity in middle adulthood.

Validity of a new automated software program for visceral adipose tissue estimation

Introduction:Given the considerable time and research cost of analyzing biomedical images to quantify adipose tissue volumes, automated image analysis methods are highly desirable. Hippo Fat™ is a new software program designed to automatically quantify adipose tissue areas from magnetic resonance images without user inputs. Hippo Fat™ has yet to be independently validated against commonly used image analysis software programs.Objective:Our aim was to compare estimates of VAT (visceral adipose tissue) and SAT (subcutaneous adipose tissue) using the new Hippo Fat™ software against those from a widely used, validated, computer-assisted manual method (slice-O-matic version 4.2, Tomovision, Montreal, CA, USA) to assess its potential utility for large-scale studies.Methods:A Siemens Magnetom Vision 1.5-T whole-body scanner and a T1-weighted fast-spin echo pulse sequence were used to collect multiple, contiguous axial images of the abdomen from a sample of 40 healthy adults (20 men) aged 18–77 years of age, with mean body mass index of 29 kg/m2 (range=19–43 kg/m2).Results:Hippo Fat™ provided estimates of VAT and SAT that were highly correlated with estimates using slice-O-matic (R 2>0.9). Average VAT was 9.4% lower and average SAT was 3.7% higher using Hippo Fat™ compared to slice-O-matic; the overestimation of SAT tended to be greater among individuals with greater adiposity. Individual-level differences for VAT were also substantial; Hippo Fat™ gave estimates of VAT ranging from 1184 cm3 less to 566 cm3 more than estimates for the same person using slice-O-matic.Conclusion:Hippo Fat™ provides a rapid method of quantifying total VAT, although the method does not provide estimates that are interchangeable with slice-O-matic at either the group (mean) or individual level.

Bisphenol A and cardiometabolic risk factors in obese children

BACKGROUND AND OBJECTIVE Bisphenol-A (BPA) is an endocrine disruptor (ED) that has been associated with obesity and metabolic changes in liver in humans. Non-alcoholic fatty liver disease (NAFLD) affects 40% of all obese children in the United States. Association of BPA with NAFLD in children is poorly understood. We investigated if BPA might play a role. METHODS In a cross sectional study of 39 obese and overweight children aged 3-8 years enrolled from the Children Medical Center of Dayton, Ohio, anthropometric, clinical and biochemical assessment of serum samples were conducted. Urinary BPA was measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and was adjusted for urinary creatinine BPA (creatinine) using linear regression and spline analyses. RESULTS Higher urinary BPA (creatinine) concentration in overweight and obese children was associated with increasing free thyroxine. In male children BPA (creatinine) decreased with age, and was associated with elevated liver enzyme aspartate aminotransferase and diastolic blood pressure. The association of BPA (creatinine) persisted even after adjusting for age and ethnicity. Also in males, BPA concentration unadjusted for creatinine was significantly associated with serum fasting insulin and homeostasis model assessment for insulin resistance (HOMA-IR) showing non-monotonic exposure-response relationship. CONCLUSION Urinary BPA in obese children, at least in males is associated with adverse liver and metabolic effects, and high diastolic blood pressure.

A changing pattern of childhood BMI growth during the 20th century: 70 y of data from the Fels Longitudinal Study

BACKGROUND The BMI distribution shifted upward in the United States between the 1960s and the 1990s, but little is known about secular trends in the pattern of BMI growth, particularly earlier in the century and early in childhood. OBJECTIVE The objective was to examine differences in BMI growth in children born in 1929-1999. DESIGN BMI curves from ages 2 to 18 y were produced for 855 European-American children in the Fels Longitudinal Study born in 1929-1953, 1954-1972, and 1973-1999. Age (A(min)) and BMI (BMI(min)) at adiposity rebound and age (AV(max)), BMI (BMIV(max)), and velocity (V(max)) at maximum velocity were derived; multivariable regression was used to examine whether maternal BMI, infant weight gain, and other covariates mediated the cohort effects on these traits. RESULTS BMI curves showed that children born in 1973-1999 had the lowest BMI values until age 5 y but had the largest values from age 8 y onward. In adjusted models, boys and girls born in 1973-1999 had a 0.15-kg/m(2) per year faster V(max) and a 1-kg/m(2) higher BMIV(max) than did children of the same sex born in 1929-1953, and girls had a 0.8-y earlier A(min) (P < 0.01). Maternal BMI and infant weight gain were associated with an obesity-prone pattern of BMI growth but did not account for the observed trends. CONCLUSIONS Shifts in the BMI growth rate around the time of pubertal initiation were apparent starting after 1973. The BMI growth curve did not increase monotonically over time; rather, children born during the obesity epidemic were characterized by lower BMI values before the adiposity rebound and by rapid subsequent BMI gain.

Genetic analysis of self-reported physical activity and adiposity: the Southwest Ohio Family Study.

OBJECTIVE Physical inactivity poses a major risk for obesity and chronic disease, and is influenced by both genetic and environmental factors. However, the genetic association between physical activity (PA) level and obesity is not well characterized. Our aims were to: (i) estimate the extent of additive genetic influences on physical activity while adjusting for household effects; and (ii) determine whether physical activity and adiposity measures share common genetic effects. SUBJECTS The sample included 521 (42 % male) adult relatives, 18-86 years of age, from five large families in the Southwest Ohio Family Study. DESIGN Sport, leisure and work PA were self-reported (Baecke Questionnaire of Habitual Physical Activity). Total body and trunk adiposity, including percentage body fat (%BF), were measured using dual-energy X-ray absorptiometry. Abdominal visceral and subcutaneous adipose tissue mass were measured using MRI. RESULTS Heritabilities for adiposity and PA traits, and the genetic, household and environmental correlations among them, were estimated using maximum likelihood variance components methods. Significant genetic effects (P < 0.05) were found for sport (h2 = 0.26) and leisure PA (h2 = 0.17). Significant (P < 0.05) household effects existed for leisure PA (c2 = 0.25). Sport PA had a negative genetic correlation with central adiposity measurements adjusted for height (rhoG > |-0.40|). Sport and leisure PA had negative genetic correlations with %BF (rhoG > |-0.46|). CONCLUSIONS The results suggest that the association of sport and leisure PA with lower adiposity is due, in part, to a common genetic inheritance of both reduced adiposity and the predisposition to engage in more physical activity.

The positive association of obesity variants with adulthood adiposity strengthens over an 80-year period: A gene-by-birth year interaction

Objective: To test the hypothesis that the statistical effect of obesity-related genetic variants on adulthood adiposity traits depends on birth year. Methods: The study sample included 907 related, non-Hispanic White participants in the Fels Longitudinal Study, born between 1901 and 1986, and aged 25-64.99 years (474 females; 433 males) at the time of measurement. All had both genotype data from which a genetic risk score (GRS) composed of 32 well-replicated obesity-related common single nucleotide polymorphisms was created, and phenotype data [including body mass index (BMI), waist circumference, and the sum of four subcutaneous skinfolds]. Maximum likelihood-based variance components analysis was used to estimate trait heritabilities, main effects of GRS and birth year, GRS-by-birth year interaction, sex, and age. Results: Positive GRS-by-birth year interaction effects were found for BMI (p < 0.001), waist circumference (p = 0.007), and skinfold thickness (p < 0.007). For example, each one-allele increase in GRS was estimated to result in a 0.16 increase in BMI among males born in 1930 compared to a 0.47 increase among those born in 1970. Conclusions: These novel findings suggest the influence of common obesity susceptibility variants has increased during the obesity epidemic.

Characterization of the Infant BMI Peak: Sex Differences, Birth Year Cohort Effects, Association with Concurrent Adiposity, and Heritability

To characterize an early trait in the BMI‐for‐age curve, the infant BMI peak.