[Show abstract][Hide abstract] ABSTRACT: The link between central adiposity and osteopenia has not been extensively studied in Latina women. In particular, the association between abdominal weight and bone mineral content (BMC) and bone mineral density (BMD), independent of total weight and aerobic capacity, remains uncertain, especially in overweight and obese individuals.
Trunk weight, total body fat mass, fat-free mass, BMC, and BMD of 33 premenopausal Latina women age 22 to 51 years from Los Angeles, California were measured using dual-energy X-ray absorptiometry (DXA). Waist circumference (WC) was measured without clothing at the smallest circumference of the torso. Peak aerobic capacity (peak VO2) was determined by treadmill ergometry with direct measurement of oxygen consumption.
Partial correlations controlling for total body fat mass, fat-free mass, and peak VO2 revealed a significant inverse relationship between BMC and WC (r = -0.54, P < 0.05) but not between BMD and WC (r = -0.18, P = 0.41). Similarly, while controlling for total body fat, fat-free mass, and peak VO2, BMC was inversely associated with trunk fat (r = -0.75, P < 0.001), with trunk lean (r = -0.61, P < 0.05) and with total trunk weight (r = -0.75, P < 0.001); results were non-significant for BMD. When these analyses were repeated separately in overweight (n = 10) versus in the obese (n = 18) women, inverse relationships between BMC and trunk fat as well as between BMC and total trunk weight became stronger in the obese compared with the overweight women.
Although general obesity may prevent osteoporosis, these findings suggest that abdominal obesity (ie, trunk weight) specifically and independently may adversely influence bone mass.
Clinical medicine insights. Women's health. 01/2013; 6:25-30.
[Show abstract][Hide abstract] ABSTRACT: The link between abdominal fat and bone mineral content (BMC), independent of weight, has not been extensively studied. In Latino children, the contributions of abdominal subcutaneous and visceral fat to BMC have not been examined. Research on the effect of leptin on BMC has also been inconclusive.
The present study included 256 overweight Latino children (111 girls, 145 boys; mean BMI 28.2; age 11.1 +/- 1.7 years) from Los Angeles, California. Subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue (IAAT) were determined by single-slice magnetic resonance imaging. BMC was measured using dual-energy X-ray absorptiometry.
Independent of age, Tanner stage and weight, abdominal adipose tissue (SAAT + IAAT) was inversely correlated with BMC (r = -0.46, p < 0.0001; n = 256). In girls, there was an inverse correlation between SAAT and BMC (r = -0.38, p < 0.05), between IAAT and BMC (r = -0.32, p < 0.05) and between leptin and BMC (r = -0.39, p < 0.05). In boys, SAAT and BMC were inversely correlated (r = -0.26, p < 0.05), but the correlation between IAAT and BMC was not significant (p = 0.22). Leptin was also inversely correlated with BMC (r = -0.38, p < 0.05) in boys and contributed to the variances in BMC in both girls and boys.
Total abdominal adipose fat and leptin are negatively associated with BMC in Latino children. The correlation between SAAT and BMC is stronger in girls than boys. IAAT and BMC are negatively associated in girls but not correlated in boys.
Hormone Research 01/2009; 72(2):82-7. · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the association between resting energy expenditure (REE) and bone mineral density (BMD) in white adults.
White, middle-class to upper middle-class community-dwelling adults.
Women (n = 996) and men (n = 686) aged 36 to 97 years.
REE calculated using the Harris-Benedict equation.
BMD of the lumbar spine (L1 to L4), total hip, and total body measured using dual energy x-ray absorptiometry.
REE was lower in women than in men (1220 versus 1566 kcal/day, P < 0.0001); women also had lower BMI. After adjusting for lean body mass (LBM), REE was higher in women than men (1407 versus 1296 kcal/kg LBM/d, P < 0.0001). In stepwise multiple linear regression models, REE explained 13% of variance in spine BMD in women and 6% in men, 33% of variance in hip BMD in women and 22% in men, and 32% of variance in total body BMD in women and 22% in men. In women, weight explained 10% less of the hip BMD variance and 6% less of the total body BMD variance than REE. In men, weight explained 4% more of the spine BMD variance and 1% more of the total body BMD variance than REE.
REE explained more of the BMD variance than weight in women, and the reverse was true in men. These sex differences were largely explained by sex differences in LBM or weight.
Clinical journal of sport medicine: official journal of the Canadian Academy of Sport Medicine 01/2009; 19(1):39-45. · 1.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In adults, hypertension has been shown to be inversely correlated with bone mineral content (BMC); however, the association between blood pressure (BP) and BMC has not been studied in pediatrics.
Total body BMC of 187 overweight (mean BMI = 28.7 kg/m(2)) Latino children and adolescents (mean age = 11.2 years) were measured using dual-energy x-ray absorptiometry. Seated systolic BP (SBP) and diastolic BP (DBP) were measured using a standard mercury sphygmomanometer. Hypertension was defined by SBP or DBP above the 90(th) percentile for height, age, and sex.
Partial correlations revealed an inverse association between SBP and BMC (r = -0.24, P = 0.02) in boys (n = 105); results were nonsignificant (P = 0.27) in girls (n = 82). There were no significant correlations between DBP and BMC. When BMI and insulin sensitivity were adjusted for, hypertensive boys (n = 21) had lower BMC (1435 v 1636 g; P = 0.03) than normotensive boys (n = 84); similarly, hypertensive girls (n = 25) had lower BMC (1438 v 1618 g; P = 0.02) than normotensive girls (n = 57). In postpubertal adolescents (Tanner stage 4-5; n = 48), inverse correlations were stronger (r = -0.40, P = 0.007); results were nonsignificant in prepubertal and pubertal children (Tanner stage 1-3; n = 139, P = 0.57). In postpubertal girls (n = 37), there were no significant correlations (P = 0.14); inverse correlations in postpubertal boys (n = 11) became markedly stronger (r = -0.80, P = 0.02).
Based on the study findings, SBP is inversely correlated with BMC in overweight adolescents; additionally, hypertensive subjects have lower adjusted means of BMC than normotensive subjects. These promising new findings suggest that hypertension may be a risk factor for osteopenia in overweight children and adolescents; this risk may be exacerbated in postpubertal boys.
American Journal of Hypertension 03/2007; 20(2):190-6. · 3.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Total fat mass plays a significant role in determining bone mass, but the specific role of central adiposity independent of total fat mass has not been widely studied. Prepubertal (Tanner 1) children (n = 181; 65 boys, 116 girls, 7.8 +/- 1.5 years), including 99 Caucasians and 82 African Americans from Birmingham, Alabama, participated in this study. Body composition, including total body and trunk fat mass, and bone mineral content (BMC) were measured using dual-energy X-ray absorptiometry. Subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue (IAAT) were determined by single-slice computed tomography (CT). After adjusting for gender, age, height, total fat, and lean mass, trunk weight was inversely correlated with BMC in Caucasians (r = -0.56, P < 0.0001) and in African Americans (r = -0.37, P < 0.05). In Caucasians, independent of gender, age, height, total fat, and lean mass, there was an inverse correlation between SAAT and BMC (r = -0.58, P < 0.0001) but no significant correlation between IAAT and BMC; in addition, SAAT explained 6% of the variance in BMC. In contrast, in African Americans, SAAT and BMC were not significantly correlated. However, while adjusting for gender, age, height, SAAT, total fat, and lean mass, an inverse association between IAAT and BMC was observed in African Americans (r = -0.50, P < 0.01); IAAT also explained 3% of the variance in BMC. These findings suggest that, in general, total abdominal weight is negatively associated with bone mass, but there appear to be racial differences with regard to the contributions of subcutaneous and visceral fat to BMC in prepubertal children.
Calcified Tissue International 01/2007; 79(6):383-8. · 2.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previous studies have shown that hypertension is related to abnormalities of calcium metabolism such as increased calcium losses from kidney and secondary activation of parathyroid glands. In animal studies, high blood pressure (BP) has been shown to increase the risk of bone mineral loss; however whether hypertension is associated with reduced bone mineral content (BMC) in human beings is inconclusive. The relationship between BP and BMC has not been previously studied in Hispanic individuals.
Total body BMC of 33 overweight and obese (mean BMI= 31.1 kg/m(2)) premenopausal Hispanic women 22 to 51 years of age from Los Angeles, CA, was measured using dual-energy x-ray absorptiometry. Seated systolic BP (SBP) and diastolic BP (DBP) were measured using a standard mercury sphygmomanometer.
Partial correlations revealed an inverse relationship among BMC and SBP (r = -0.61, P < .001), DBP (r = -0.52, P < .01), and hypertension (r = -0.69, P < .0001). In multiple linear regressions, SBP was negatively related (beta = -0.31, P = .001) to BMC and explained 10% of the variance. The DBP did not make a significant contribution to the variance. When fat mass and fat-free mass were controlled for, hypertensive women (n = 9) had significantly lower BMC (2119 g v 2441 g; P < .0001) than normotensive women (n = 23).
These results reveal that BMC is partially and inversely correlated with resting SBP and DBP in premenopausal Hispanic women; in addition hypertensive women have lower adjusted means of BMC than normotensive women. Sustained hypercalciuria and ensuing hyperparathyroidism as consequences of high BP may be the mechanisms that explain the pathophysiology of increased bone mineral loss in hypertension.
American Journal of Hypertension 04/2006; 19(3):286-92. · 3.67 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: African-American women tend to be more overweight and to have lower resting energy expenditures (REE) compared with Caucasian women. Weight is associated with bone mineral density (BMD), but the relation between BMD and REE has not been reported.
Four hundred postmenopausal African-American women aged 45-87 (yr) from San Diego, CA participated in this community-based cross-sectional study. Body composition (fat mass, lean body mass), bone mineral content (BMC) and BMD of the lumbar spine, hip (femoral neck, greater trochanter, intertrochanter), and total body were measured using dual energy x-ray absorptiometry (DXA). REE was calculated using the Harris-Benedict equation; grip strength was measured by isometric dynamometry.
REE (r range: 0.32-0.79) showed the strongest correlation with spine, total hip, and total body BMC and BMD. In stepwise multiple linear regressions adjusted for age and grip strength, REE explained 15% of the variance in spine BMD, 33% of the variance in total hip, and 32% of the total body BMD variance. REE explained 63% of the total body BMC variance. When body weight replaced REE in the models, weight became the strongest covariate of BMC and BMD but explained 1% less of the variance in spine BMD, 5% less of the variance in total hip BMD, 4% less of the variance in total body BMD, and 3% less of the variances in spine, total hip, and total body BMC than did REE.
In this cohort of African-American women, weight explained less of the BMC and BMD variance than REE. Poor energy economy may contribute to being overweight and may explain the lower rates of osteoporosis observed in African-American women.
Medicine & Science in Sports & Exercise 08/2005; 37(7):1203-10. · 4.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Research on the skeletal status of pre-diabetic (type 2 diabetic) children is warranted. We examined the hypothesis that bone mineral content (BMC) and bone mineral density (BMD) will be lower in children with impaired glucose tolerance (IGT) versus normal glucose tolerance (NGT).
Total body BMC and BMD of 184 overweight Latino children (106 boys, 78 girls, 11.9 +/- 1.7 years) with a family history of type 2 diabetes were measured using dual-energy X-ray absorptiometry. Glucose tolerance was assessed by 2-h glucose after an oral glucose tolerance test. Area under the insulin curve (AUC) assessed the cumulative insulin response to oral glucose. Acute insulin response to glucose (AIR) was determined by an intravenous glucose tolerance test.
Partial correlations revealed an inverse relationship between BMC and AIR (r = -0.29, P = 0.00), AUC (r = -0.28, P = 0.00), fasting insulin (r = -0.16, P = 0.04), and 2-h insulin (r = -0.16, P = 0.04). There was no significant difference in BMC or BMD between children with IGT (n = 46) or NGT (n = 138). Stepwise multiple linear regression revealed that 89% of the variance in BMC is attributed to lean mass (87%), age (1%), and AIR (1%). BMD was explained by lean mass (69%), Tanner stage (3%), and AUC (2%).
The findings of this study suggest that in overweight children, lean mass is the primary predictor of BMC and BMD, whereas age, Tanner stage, and the acute and cumulative insulin responses to oral glucose make subtle independent contributions to the total variances. In addition, poor glycemic control does not seem to be detrimental to bone mass of pre-diabetic children.
Diabetes Care 03/2005; 28(2):372-8. · 7.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hispanics comprise one of the fastest-growing segments of the U.S. population. Mexican-American adults are more likely to be overweight, physically inactive, diabetic, and to have higher levels of hypertension than are white adults. However, studies addressing the relationship between physical fitness and coronary artery disease (CAD) risk factors among Mexican-Americans are much less conclusive. Therefore, understanding the etiology of factors influencing resting systolic (SBP) and diastolic blood pressure (DBP) in Hispanic women was the aim of this investigation. SBP, DBP, peak oxygen uptake (peak VO (2)), weekly physical activity, waist (WC) and hip circumference, blood glucose, and levels of plasma lipids (triglyceride, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol) of 39 Hispanic women age 22 - 51 years were measured. Factors with significant correlation to SBP were age, WC, sagittal diameter, and weight. Similarly, significant correlations were observed between anthropometric indices, age, and DBP. Peak VO (2) ( r = - 0.53, p < 0.01) and heart rate at maximal effort ( r = - 0.34, p </= 0.05) were inversely associated to DBP. There was also a strong inverse correlation ( r = - 0.53, p < 0.01) between peak VO (2) and CAD risk profile (created from one or the combination of: hypertension, obesity, hyperglycemia, dyslipidemia, smoking). Stepwise multiple linear regression revealed that 33 % of the variance in SBP is attributed to age (25 %), and WC (8 %), while DBP is explained by WC alone (26 %). The addition of peak VO (2) did not make significant contributions to the variances in SBP or DBP. The findings of this study suggest that central adiposity is an important predictor of resting blood pressure in Hispanic women. The inverse association between aerobic fitness and diastolic blood pressure as well as CAD risk factors suggests that recommendations regarding prevention of hypertension in this population should be based on the interrelationships between physical fitness and obesity.
International Journal of Sports Medicine 11/2004; 25(8):599-606. · 2.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Understanding the etiology of factors influencing bone mineral density (BMD) in Hispanic women for the prevention of osteoporosis was the aim of this investigation. Whole body BMD (WBBMD) of 39 Hispanic, premenopausal women aged 22 - 51 years was measured using dual-energy X-ray absorptiometry (DXA). Maximal aerobic capacity ((.-)VO(2max)) was determined by treadmill ergometry with direct measurement of oxygen consumption. Fat-free mass (FFM) and fat mass were estimated from two independent techniques, DXA and bioelectrical impedance analysis (BIA). A questionnaire was administered to determine weekly physical activity, age of menarche, oral contraceptive (OC) use, parity, and lactation. Factors with significant correlation to WBBMD were weight ( r = 0.74), body mass index ( r = 0.66), fat mass ( r = 0.68 - 0.69), FFM ( r = 0.55 - 0.65), percent fat ( r = 0.43 - 0.55), sagittal diameter ( r = 0.58), waist circumference ( r = 0.53), hip circumference ( r = 0.66) and weekly activity ( r = 0.40). Stepwise multiple linear regression revealed that 73 % of the variance in WBBMD is attributed to fat mass (55 %), FFM (10 %), and (.-)VO(2max) (8 %). When BIA was used instead of DXA in the regression, (.-)VO(2max) was no longer an independent predictor of WBBMD. Fat mass and FFM accounted for 43 % and 20 % of the variance in WBBMD, respectively, explaining a total of 63 % of the variance. The addition of age, age of menarche, weekly physical activity, OC use, parity, and lactation did not make significant contributions to the variance. The findings of this study suggest that fat mass is a stronger predictor of bone mineral density than fat-free mass to BMD; aerobic capacity is another important predictor of BMD in Hispanic premenopausal women.
International Journal of Sports Medicine 08/2004; 25(5):384-90. · 2.27 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Research addressing the role of biology and behavior on bone development during times of peak bone acquisition in adolescence is limited. The present investigation was conducted to address the influence of body composition (lean body mass, fat mass), menarche, leisure physical activity, sports team participation, smoking, and second-hand smoke on skeletal mass of a unique sample of Asian adolescents in China.
A total of 166 girls and 300 boys (ages 12-16 yr) participated in this study. Bone mineral density (BMD) and content (bone mineral content (BMC)) of the forearm and the os calcis were measured using dual energy x-ray absorptiometry (DXA); lean body mass (LBM) and fat mass were estimated by bioelectrical impedance analysis (BIA); grip strength was measured by isometric dynamometry. Menarche, leisure physical activity, sports team participation, and active and passive smoking were determined using questionnaire.
In girls, a total of 44% of the variance in forearm BMC was attributed to a model which included LBM (32%), time since menarche (10%), and age (2%); heel BMC was best predicted by LBM alone (42%), with no significant contribution by other variables. In boys, a total of 39% of the variance in forearm BMC was attributed to a model which included LBM (28%), age (5%), sports team participation (4%), height (1%), and fat mass (1%); heel BMC was best predicted by LBM (50%) and height (3%), accounting for 53% of the variance.
The findings of this study suggest that lean body mass is the primary determinant of bone mass in Chinese adolescents. Menarche is also an important contributor in girls, whereas age and sports team participation are secondary predictors of bone mass in boys.
Medicine & Science in Sports & Exercise 06/2003; 35(5):720-9. · 4.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: African-American women have a long-standing approximately 20% higher breast cancer incidence rate than USA White women under age 40 while rates among Latinas are lower than those of Whites. The reasons for this are not clear, however they may be due to ethnic differences in circulating oestradiol and progesterone levels. In a cross-sectional study, we investigated whether anovulation frequency and circulating serum oestradiol and/or progesterone levels vary among normally cycling nulliparous African-American (n=60), Latina (n=112) and non-Latina White (n=69) women. Blood and urine specimens were collected over two menstrual cycles among healthy 17- to 34-year-old women. Frequency of anovulation was greater among White women (nine out of 63, 14.3%) than African-American women (four out of 56, 7.1%) or Latina women (seven out of 102, 6.9%), although these differences were not statistically significant. African-American women had 9.9% (P=0.26) higher follicular phase oestradiol concentrations than Latina women and 17.4% (P=0.13) higher levels than White women. African-American women also had considerably higher levels of luteal phase oestradiol (vs Latinas, +9.4%, P=0.14; vs Whites, +25.3%, P=0.003) and progesterone (vs Latinas, +15.4%, P=0.07; vs Whites, +36.4%, P=0.002). Latina women were also observed to have higher follicular oestradiol, and luteal oestradiol and progesterone levels than White women (follicular oestradiol: +6.8%, P=0.48; luteal oestradiol: +14.6%, P=0.04; luteal progesterone: +18.2%, P=0.06). These results suggest that exposure to endogenous steroid hormones may be greater for young African-American and Latina women than for Whites.
British Journal of Cancer 03/2002; 86(3):367-71. · 5.08 Impact Factor