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1.
J Pediatr Gastroenterol Nutr ; 57(5): 587-93, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23760229

RESUMO

BACKGROUND: Vitamin D deficiency and low bone mineral density (BMD) are complications of inflammatory bowel disease. Vitamin D deficiency is more prevalent among African Americans compared with whites. There are little data comparing differences in serum 25-hydroxyvitamin D (25OHD) concentrations and BMD between African American and white children with Crohn disease (CD). METHODS: We compared serum 25OHD concentrations of African American children with CD (n = 52) to white children with CD (n = 64) and healthy African American controls (n = 40). We also analyzed BMD using dual-energy x-ray absorptiometry results from our pediatric CD population. RESULTS: African American children with CD had lower serum 25OHD concentrations (16.1 [95% confidence interval, CI 14.5-17.9] ng/mL) than whites with CD (22.3 [95% CI 20.2-24.6] ng/mL; P < 0.001). African Americans with CD and controls exhibited similar serum 25OHD concentration (16.1 [95% CI 14.5-17.9] vs 16.3 [95% CI 14.4-18.4] ng/mL; NS). African Americans with CD exhibited no difference in serum 25OHD concentration when controlling for seasonality, disease severity, and surgical history, although serum 25OHD concentration was significantly decreased in overweight children (body mass index ≥85%, P = 0.003). Multiple regression analysis demonstrated that obese African American girls with CD had the lowest serum 25OHD concentrations (9.6 [95% CI 6.8-13.5] ng/mL). BMD was comparable between African American and white children with CD (z score -0.4 ± 0.9 vs -0.7 ± 1.2; NS). CONCLUSIONS: African American children with CD are more likely to have vitamin D deficiency compared with white children with CD, but have similar BMD. CD disease severity and history of surgery do not affect serum 25OHD concentrations among African American children with CD. African American children have low serum 25OHD concentrations, independent of CD, compared with white children. Future research should focus on how race affects vitamin D status and BMD in children with CD.


Assuntos
Reabsorção Óssea/etiologia , Doença de Crohn/fisiopatologia , Estado Nutricional , Deficiência de Vitamina D/etiologia , 25-Hidroxivitamina D 2/sangue , Adolescente , Adulto , Negro ou Afro-Americano , Índice de Massa Corporal , Densidade Óssea , Reabsorção Óssea/epidemiologia , Reabsorção Óssea/etnologia , Reabsorção Óssea/fisiopatologia , Calcifediol/sangue , Criança , Estudos de Coortes , Doença de Crohn/sangue , Doença de Crohn/complicações , Doença de Crohn/etnologia , Estudos Transversais , Feminino , Georgia/epidemiologia , Humanos , Masculino , Estado Nutricional/etnologia , Sobrepeso/complicações , Prevalência , Estudos Prospectivos , Índice de Gravidade de Doença , Deficiência de Vitamina D/epidemiologia , Deficiência de Vitamina D/etnologia , Deficiência de Vitamina D/fisiopatologia , População Branca , Adulto Jovem
2.
J Clin Endocrinol Metab ; 98(7): 2854-63, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23666961

RESUMO

OBJECTIVE: Our objective was to characterize changes in bone resorption in relation to the final menstrual period (FMP), reproductive hormones, body mass index (BMI), and ethnicity. METHODS: Urinary type I collagen N-telopeptide (NTX), estradiol, and FSH levels were measured annually for up to 8 years spanning the menopause transition in 918 African American, Chinese, Japanese, or Caucasian women. RESULTS: Urinary NTX began to increase sharply about 2 years before the FMP, reaching its peak level about 1 to 1.5 years after the FMP. NTX levels declined modestly from 2 to 6 years after the FMP but remained about 20% higher than before the menopause transition. The sharp rise in FSH occurred in conjunction with a sharp decline in estradiol and shortly after FSH levels began increasing rapidly. The mean increase in urinary NTX across the menopause transition was greatest in women with BMI <25 kg/m² and smallest in women with BMI >30 kg/m². Increases in NTX were greatest in Japanese women and smallest in African Americans. These differences were attenuated, but not eliminated, when analyses were adjusted for covariates, particularly BMI. SUMMARY: During the menopause transition, a decline in ovarian function beginning about 2 years before the FMP is followed by an increase in bone resorption and subsequently by bone loss. The magnitude of the increase in bone resorption is inversely associated with BMI. Ethnic differences in changes in bone resorption are attenuated, but not eliminated, by adjustment for BMI. Ethnic differences in BMI, and corresponding ethnic differences in bone resorption, appear to account for much of the ethnic variation in perimenopausal bone loss.


Assuntos
Reabsorção Óssea/etiologia , Estradiol/sangue , Hormônio Foliculoestimulante Humano/sangue , Menopausa , Obesidade/fisiopatologia , Osteoporose Pós-Menopausa/etiologia , Sobrepeso/fisiopatologia , Adulto , Negro ou Afro-Americano , Asiático , Índice de Massa Corporal , Reabsorção Óssea/sangue , Reabsorção Óssea/etnologia , Reabsorção Óssea/urina , China/etnologia , Estudos de Coortes , Colágeno/urina , Feminino , Humanos , Japão/etnologia , Estudos Longitudinais , Menopausa/etnologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/sangue , Osteoporose Pós-Menopausa/etnologia , Osteoporose Pós-Menopausa/urina , Ovário/fisiopatologia , Estados Unidos , População Branca
3.
Endocr J ; 60(5): 643-50, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23327841

RESUMO

Osteoporosis causes an enormous health and economic impact in Japan. We investigated the relation between lifestyle and bone fracture in middle-aged and elderly women. This was a population-based, multicenter, cross-sectional survey for postmenopausal osteoporosis in Chiba City, Japan (Chiba bone survey). This survey included 64,809 Japanese women aged > 40 years. All participants underwent anthropometric measurements including bone mineral density (BMD) and completed a structured, nurse-assisted, self-administered questionnaire also including patient lifestyle. Bone fracture during the recent 5 years was observed in 5.3%, and the fracture group had significantly higher age, BMI, and prevalence of delivery, family histories of kyphosis and hip fracture, diabetes mellitus (DM), dyslipidemia, kidney disease, exercise, fall, and osteoporosis, and had significantly lower BMD and proportion of menstruating participants. Logistic regression analysis revealed that bone fracture was closely associated with not only low bone mass but also age, fall, family histories of kyphosis and hip fracture, DM, kidney disease, menopause, and lifestyle factors of dieting, exercise, and alcohol. Women's health care focusing on lifestyle-related fracture risks such as dieting, exercise, and alcohol appears necessary to prevent bone fracture in postmenopausal osteoporosis.


Assuntos
Estilo de Vida , Osteoporose Pós-Menopausa/fisiopatologia , Fraturas por Osteoporose/etiologia , Acidentes por Quedas , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Reabsorção Óssea/etnologia , Reabsorção Óssea/fisiopatologia , Estudos Transversais , Saúde da Família , Feminino , Inquéritos Epidemiológicos , Fraturas do Quadril/etnologia , Humanos , Incidência , Japão/epidemiologia , Cifose/etnologia , Estilo de Vida/etnologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/etnologia , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/etnologia , Fatores de Risco
4.
Endocrine ; 42(2): 423-9, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22407492

RESUMO

Osteoporosis is a disease associated with insulin resistant states such as central obesity, diabetes, and metabolic syndrome. Non-alcoholic fatty liver disease (NAFLD) is also increased in such conditions. However, little is known about whether osteoporosis and nonalcoholic fatty liver disease are etiologically related to each other or not. We examined whether bone mineral density (BMD) is associated with NAFLD in pre- and postmenopausal women. Four hundred eighty-one female subjects (216 premenopausal and 265 postmenopausal) were enrolled. Lumbar BMD was measured using dual-energy X-ray absorptiometry. Liver ultrasonography was done to check the severity of fatty liver. We excluded subjects with a secondary cause of liver disease. Blood pressure, lipid profile, fasting plasma glucose, alanine aminotransferase (ALT), aspartate aminotransferase, and body mass index were measured in every subject. Mean lumbar BMD was lower in subjects with NAFLD than those without NAFLD in postmenopausal women (0.98 ± 0.01 vs. 1.01 ± 0.02 g/cm², P = 0.046). Multiple correlation analysis revealed a significant association between mean lumbar BMD and NAFLD in postmenopausal subjects after adjusting for age, body mass index, ALT, smoking status, and alcohol consumption (ß coefficient -0.066, 95% CI -0.105 to -0.027, P = 0.001). Even after adjusting the presence of metabolic syndrome, the significance was maintained (ß coefficient -0.043, 95% CI -0.082 to -0.004, P = 0.031). Lumbar BMD is related with NAFLD in postmenopausal females. We suggest that postmenopausal women with NAFLD may have a higher risk of osteoporosis than those without.


Assuntos
Reabsorção Óssea/complicações , Fígado Gorduroso/complicações , Fígado/fisiopatologia , Osteoporose Pós-Menopausa/complicações , Pós-Menopausa , Adulto , Densidade Óssea , Reabsorção Óssea/epidemiologia , Reabsorção Óssea/etnologia , Estudos Transversais , Fígado Gorduroso/epidemiologia , Fígado Gorduroso/etnologia , Fígado Gorduroso/fisiopatologia , Feminino , Hospitais Universitários , Humanos , Fígado/diagnóstico por imagem , Vértebras Lombares , Pessoa de Meia-Idade , Modelos Biológicos , Hepatopatia Gordurosa não Alcoólica , Osteoporose Pós-Menopausa/epidemiologia , Osteoporose Pós-Menopausa/etnologia , Pré-Menopausa , Prevalência , República da Coreia/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Índice de Gravidade de Doença , Ultrassonografia
6.
Osteoporos Int ; 23(5): 1503-12, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-21811862

RESUMO

UNLABELLED: Among a group of 940 US adults, economic adversity and minority race status were associated with higher serum levels of markers of bone turnover. These results suggest that higher levels of social stress may increase bone turnover. INTRODUCTION: To determine socioeconomic status (SES) and race differences in levels of bone turnover. METHODS: Using data from the Biomarker Substudy of the Midlife in the US (MIDUS) study (491 men, 449 women), we examined cross-sectional associations of SES and race with serum levels of bone turnover markers (bone-specific alkaline phosphatase [BSAP], procollagen type I N-terminal propeptide [PINP], and N-telopeptide [Ntx]) separately in men and women. Linear multivariable regression was used to control for body weight, menopausal transition stage, and age. RESULTS: Among men, low family poverty-to-income ratio (FPIR) was associated with higher turnover, but neither education nor race was associated with turnover. Men with FPIR <3 had 1.808 nM BCE higher Ntx (P = 0.05), 3.366 U/L higher BSAP (P = 0.02), and 7.066 higher PINP (P = 0.02). Among women, neither education nor FPIR was associated with bone turnover, but Black women had 3.688 nM BCE higher Ntx (P = 0.001), 5.267 U/L higher BSAP (P = 0.005), and 11.906 µg/L higher PINP (P = 0.008) compared with non-Black women. CONCLUSIONS: Economic adversity was associated with higher bone turnover in men, and minority race status was associated with higher bone turnover in women, consistent with the hypothesis that higher levels of social stresses cause increased bone turnover. The magnitude of these associations was comparable to the effects of some osteoporosis medications on levels of turnover.


Assuntos
Remodelação Óssea/fisiologia , Reabsorção Óssea/etnologia , Classe Social , Adulto , Negro ou Afro-Americano/psicologia , Idoso , Fosfatase Alcalina/sangue , Biomarcadores/sangue , Remodelação Óssea/genética , Reabsorção Óssea/sangue , Reabsorção Óssea/etiologia , Colágeno Tipo I/sangue , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/sangue , Peptídeos/sangue , Pobreza , Pró-Colágeno/sangue , Caracteres Sexuais , Fatores Socioeconômicos , Estresse Psicológico/sangue , Estresse Psicológico/complicações , Estresse Psicológico/etnologia , Estados Unidos/epidemiologia
7.
Am J Clin Nutr ; 94(4): 1063-70, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21865328

RESUMO

BACKGROUND: Fat mass is thought to be protective against osteoporosis, primarily because of its weight-bearing effect. Few studies have evaluated the association between abdominal fat mass (AFM) and bone health beyond its weight-bearing effect. OBJECTIVE: We tested the hypothesis that higher body weight-adjusted AFM is associated with poor bone health. DESIGN: A cross-sectional study was conducted in 629 Puerto Rican adults aged 47-79 y. Bone mineral density (BMD) of the femoral neck, trochanter, total femur, and lumbar spine (L2-L4) were measured by using dual-energy X-ray absorptiometry (DXA). AFM and total fat mass (TFM) were assessed by using body-composition software from whole-body DXA scans. Osteoporosis and osteopenia were defined as T-scores ≤ -2.5 and -1.0 to -2.5 SD, respectively, at the respective bone site. RESULTS: After confounders were controlled for, body weight-adjusted AFM was inversely associated with BMD at all 4 bone sites in women and at the femoral neck in men. For TFM, small inverse associations were seen at the trochanter and total femur in women. In men, similar associations were seen at the 3 femur sites. In both sexes, the odds for osteoporosis or osteopenia at each of the femoral sites increased by 10-16% for every 100-g increase in body weight-adjusted AFM. CONCLUSIONS: Higher AFM was associated with poor bone health in this Puerto Rican sample. Efforts to reduce abdominal obesity will not only reduce the risk of chronic disease but may also improve bone health. This trial is registered at clinicaltrials.gov as NCT01231958.


Assuntos
Gordura Abdominal/patologia , Densidade Óssea , Reabsorção Óssea/etnologia , Reabsorção Óssea/etiologia , Obesidade Abdominal/fisiopatologia , Adiposidade , Idoso , Índice de Massa Corporal , Doenças Ósseas Metabólicas/epidemiologia , Doenças Ósseas Metabólicas/etnologia , Doenças Ósseas Metabólicas/etiologia , Reabsorção Óssea/epidemiologia , Boston/epidemiologia , Estudos de Coortes , Estudos Transversais , Feminino , Seguimentos , Hispânico ou Latino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Abdominal/patologia , Osteoporose/epidemiologia , Osteoporose/etnologia , Osteoporose/etiologia , Porto Rico/etnologia , Fatores de Risco , Fatores Sexuais
8.
Osteoporos Int ; 22(5): 1627-31, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20658128

RESUMO

SUMMARY: Compared to white women, lower areal bone mineral density (aBMD) in middle-aged Vietnamese immigrants is due to reduced trabecular volumetric bone mineral density (vBMD), which in turn is associated with greater trabecular separation along with lower estrogen levels. INTRODUCTION: The epidemiology of osteoporosis in Asian populations is still poorly known, but we previously found a deficit in lumbar spine aBMD among postmenopausal Southeast Asian women, compared to white women, that persisted after correction for bone size. This issue was revisited using more sophisticated imaging techniques. METHODS: Twenty Vietnamese immigrants (age, 44-79 years) were compared to 162 same-aged white women with respect to aBMD at the hip, spine and wrist, vBMD at the hip and spine by quantitative computed tomography and vBMD and bone microstructure at the ultradistal radius by high-resolution pQCT. Bone turnover and sex steroid levels were assessed in a subset (20 Vietnamese and 40 white women). RESULTS: The aBMD was lower at all sites among the Vietnamese women, but femoral neck vBMD did not differ from middle-aged white women. Significant differences in lumbar spine and ultradistal radius vBMD in the Vietnamese immigrants were due to lower trabecular vBMD, which was associated with increased trabecular separation. Bone resorption was elevated and bone formation depressed among the Vietnamese immigrants, although trends were not statistically significant. Serum estradiol was positively associated with trabecular vBMD in the Vietnamese women, but their estrogen levels were dramatically lower compared to white women. CONCLUSIONS: Although reported discrepancies in aBMD among Asian women are mainly an artifact of smaller bone size, we identified a specific deficit in the trabecular bone among a sample of Vietnamese immigrants that may be related to low estrogen levels and which needs further study.


Assuntos
Povo Asiático/estatística & dados numéricos , Densidade Óssea/fisiologia , Adulto , Idoso , Biomarcadores/sangue , Remodelação Óssea/fisiologia , Reabsorção Óssea/sangue , Reabsorção Óssea/etnologia , Reabsorção Óssea/fisiopatologia , Emigrantes e Imigrantes , Estradiol/sangue , Feminino , Colo do Fêmur/fisiologia , Humanos , Vértebras Lombares/fisiologia , Pessoa de Meia-Idade , Minnesota/epidemiologia , Peptídeo Natriurético Tipo C/sangue , Rádio (Anatomia)/fisiologia , Tomografia Computadorizada por Raios X/métodos
9.
Bone ; 47(1): 49-54, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20347056

RESUMO

Little is known about the progression of bone loss during young adulthood and whether it differs between men and women. As part of the San Antonio Family Osteoporosis Study we tested whether bone mineral density (BMD) changed over time in men or women, and whether the rate of BMD change differed between the sexes. BMD of the proximal femur, spine, radius, and whole body was measured in 115 men and 202 pre-menopausal women (ages 25 to 45 years; Mexican American ancestry) by dual-energy x-ray absorptiometry at two time points (5.6 years apart), from which annual percent change-in-BMD was calculated. Likelihood-based methods were used to test whether change-in-BMD differs from zero or differs between men and women. In men, percent change-in-BMD was significantly greater than zero for the 1/3 radius (i.e. indicating a gain of BMD; Bonferroni-adjusted p<0.01), less than zero for the femoral neck, lumbar spine, ultradistal radius, and whole body (i.e. indicating a loss of BMD; p<0.01 for all), and not different than zero for the total hip (p=0.24). In women, percent change-in-BMD was greater than zero for the total hip, 1/3 radius, and whole body (p<0.01 for all), less than zero for the ultradistal radius (p<0.01), and not significantly different than zero for the femoral neck and lumbar spine (p=1.0 for both). For all skeletal sites, men experienced greater decrease in BMD (or less increase in BMD) than women; this result was observed both with and without adjustment for age, BMI, and change-in-BMI (p<0.05 for all). These results suggest that significant bone loss occurs at some skeletal sites in young men and women, and that loss of BMD is occurring significantly faster, or gain of BMD is occurring significantly slower, in young men compared to young women.


Assuntos
Reabsorção Óssea/etnologia , Reabsorção Óssea/patologia , Americanos Mexicanos/etnologia , Osteoporose/etnologia , Osteoporose/patologia , Caracteres Sexuais , Adulto , Densidade Óssea/fisiologia , Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Osteoporose/fisiopatologia , Texas , Fatores de Tempo
10.
Clin Invest Med ; 30(5): E210-23, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17892763

RESUMO

Paget's disease of bone (PDB) is a metabolic bone disease characterized by increased bone resorption followed by excessive unregulated bone formation. This results in weakened, deformed bones of increased mass in which the collagen fibres assume a haphazard irregular mosaic pattern instead of the normal parallel symmetry. PDB rarely occurs before middle age and its prevalence increases steadily with age. The overall prevalence in Caucasians is approximately 3%; although it appears to be declining. There is a geographic variation in prevalence, with highest rates found in the UK. PDB affects both men and women, with a slight predominance in men. PDB may be asymptomatic or symptomatic, depending on the bones involved; the most common symptom is pain in the affected bone. While its aetiology remains elusive, genetic factors and environmental influences are implicated. In 2002, guidelines for PDB management were developed in Great Britain and have gained worldwide acceptance. In this position paper, an Expert Panel of Canadian endocrinologists and rheumatologists examines current evidence on the diagnosis and treatment of PDB to provide Canadian recommendations. In general, diagnosis may be confirmed both by X-ray and by the biochemical marker serum alkaline phosphatase, which is elevated in 85% of individuals with untreated active PDB. Treatment is indicated for all patients with symptoms and for asymptomatic patients with active PDB in areas of the skeleton with the potential to produce complications of clinical importance. The Panel recommends treating PDB with bisphosphonates that have demonstrated superior efficacy and remission rates.


Assuntos
Reabsorção Óssea/diagnóstico , Osteíte Deformante/diagnóstico , Fatores Etários , Conservadores da Densidade Óssea/uso terapêutico , Reabsorção Óssea/tratamento farmacológico , Reabsorção Óssea/epidemiologia , Reabsorção Óssea/etnologia , Reabsorção Óssea/etiologia , Canadá , Difosfonatos/uso terapêutico , Feminino , Guias como Assunto , Humanos , Masculino , Osteíte Deformante/tratamento farmacológico , Osteíte Deformante/epidemiologia , Osteíte Deformante/etnologia , Osteíte Deformante/etiologia , Osteogênese/efeitos dos fármacos , Prevalência , Indução de Remissão , Fatores Sexuais , Reino Unido , População Branca
11.
Eur J Endocrinol ; 155(5): 693-9, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17062885

RESUMO

OBJECTIVE: To evaluate whether Pakistanis have increased bone turnover compared with ethnic Norwegians due to their high prevalence of vitamin D deficiency and secondary hyperparathyroidism, and whether the relation between bone turnover and bone mineral density (BMD) differs between Pakistanis and ethnic Norwegians. DESIGN: A cross-sectional, population-based study conducted in the city of Oslo in 2000-2001. Random samples of 132 community-dwelling Pakistani men and women of ages 40, 45, and 59-60 years, and 580 community-dwelling Norwegian men and women of ages 45 and 59-60 years are included in this substudy. METHODS: Venous serum samples were drawn for measurements of markers of the vitamin D endocrine system and the bone turnover markers osteocalcin (s-OC), bone alkaline phosphatase (s-bone ALP), and tartrate-resistant acid phosphatase (s-TRACP). BMD was measured at the forearm by single-energy X-ray absorptiometry. RESULTS: Pakistanis had higher s-bone ALP compared with Norwegians. Mean (95% CI) age-adjusted levels were 22.5 (21.0, 24.1) U/l in Pakistani men versus 19.3 (18.6, 20.1) U/l in Norwegian men, P < 0.0005, and 20.3 (18.4, 22.1) U/l in Pakistani women versus 16.7 (16.0, 17.4) U/l in Norwegian women, P = 0.001. There tended to be an inverse association between bone turnover and BMD in men and women of both ethnic groups, and it was strongest for s-bone ALP. Overall mean (95% CI) distal BMD decrease was -16 (-20, -11) mg/cm(2) per 1 s.d. increase in s-bone ALP (P < 0.0005) when adjusting for age, sex, and ethnicity. CONCLUSIONS: Except for somewhat higher s-bone ALP levels in Pakistanis, there were only minor ethnic differences in bone turnover, despite a strikingly different prevalence of secondary hyperparathyroidism. Bone turnover was inversely associated with forearm BMD in both ethnic groups.


Assuntos
Densidade Óssea/fisiologia , Reabsorção Óssea/fisiopatologia , Osteogênese/fisiologia , Fosfatase Ácida/sangue , Adulto , Fosfatase Alcalina/sangue , Reabsorção Óssea/etnologia , Estudos Transversais , Feminino , Antebraço/anatomia & histologia , Humanos , Hiperparatireoidismo Secundário/epidemiologia , Isoenzimas/sangue , Masculino , Pessoa de Meia-Idade , Noruega/epidemiologia , Osteocalcina/sangue , Paquistão/etnologia , Fosfatase Ácida Resistente a Tartarato , Deficiência de Vitamina D/fisiopatologia
12.
J Clin Endocrinol Metab ; 88(3): 1043-7, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12629083

RESUMO

Blacks develop a higher peak bone mass than whites which is associated with a reduced risk for bone fracture. The physiological basis for the difference in bone mass was investigated by metabolic balance and calcium kinetic studies in adolescent black and white girls. The hypothesis that the greater peak bone mass in blacks compared with whites is due to suppressed bone resorption was tested. Subjects were housed in a supervised environment for 3 wk during which time they consumed a controlled diet and collected all excreta. Subjects were given stable calcium isotopes orally and intravenously after 1 wk adaptation. Blacks have greater calcium retention (mean +/- SD, 11.5 +/- 6.1 vs. 7.3 +/- 4.1 mmol/d, P < 0.05) consistent with greater bone formation rates (49.4 +/- 13.5 vs. 36.5 +/- 13.6 mmol/d, P < 0.05) relative to bone resorption rates (37.4 +/- 13.2 vs. 29.4 +/- 10.9 mmol/d, P = 0.07), increased calcium absorption efficiency (54 +/- 19 vs. 38 +/- 18%, P < 0.05) and decreased urinary calcium (1.15 +/- 0.95 vs. 2.50 +/- 1.35 mmol/d, P < 0.001), compared with whites. The racial differences in calcium retention in adolescence can account for the racial differences in bone mass of adults.


Assuntos
Densidade Óssea , Remodelação Óssea/fisiologia , Reabsorção Óssea/etnologia , Cálcio/metabolismo , Adolescente , População Negra , Feminino , Humanos , Osteogênese/fisiologia , População Branca
13.
Environ Res ; 91(2): 63-70, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12584006

RESUMO

Nine hundred eight women aged 40-88 years living in a non-Cd-polluted area in Japan were analyzed for urinary cadmium (Cd), N-acetyl-beta-D-glucosaminidase (NAG) activity, beta(2)-microglobulin (B2MG) concentration, and for the stiffness index (STIFF) of calcaneal bone using an ultrasound method. The urinary Cd in the subjects, with a mean and range of 2.87 and 0.25-11.4 microg/g creatinine, respectively, showed a significant correlation with NAG but not with B2MG. STIFF was significantly inversely correlated with urinary Cd, and the association remained significant after adjusting for age, body weight, and menstrual status, suggesting a significant effect of Cd on the bone loss in these subjects without signs of Cd-induced kidney damage. A two-fold increase in urinary Cd was accompanied by a decrease in STIFF corresponding to a 1.7-year rise in age. These results emphasize the need for reassessment of the significance of Cd exposure in the general Japanese population.


Assuntos
Reabsorção Óssea/etiologia , Cádmio/efeitos adversos , Cádmio/urina , Exposição Ambiental , Acetilglucosaminidase/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea , Reabsorção Óssea/etnologia , Calcâneo/química , Feminino , Humanos , Japão/etnologia , Nefropatias/complicações , Nefropatias/etiologia , Pessoa de Meia-Idade , Análise de Regressão , População Urbana , Microglobulina beta-2/análise
14.
J Am Coll Nutr ; 21(6): 560-3, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12480802

RESUMO

OBJECTIVE: Some human studies and animal models of experimental osteoporosis have shown that soy isoflavones may be effective on bone health. In this study, we carried out an intervention study to explore the effects of dietary isoflavone on bone metabolism. METHODS: Forty healthy female postmenopausal Japanese immigrants living in Brazil were divided into two groups: isoflavone-administered (n = 20) or placebo (n = 20). Subjects in the isoflavone-administered group ingested 37.3 mg per day for 10 weeks. The collection of 24-hour urine and the measurement of bone stiffness were performed at 0 and 10 weeks. Urinary excretion of isoflavones and bone resorption markers were analyzed. RESULTS: Urinary isoflavone excretion in the isoflavone-administered group was significantly increased at weeks 3 and 10. Urinary excretion of bone resorption markers was reduced in the isoflavone-administered group, while the placebo group did not show any significant reduction. Differences in levels of urinary isoflavones and bone resorption markers between the two groups were significant. CONCLUSION: This study demonstrated that the bone resorption was associated with the intake of soy isoflavones in postmenopausal women, and continuous dietary intake of isoflavone may inhibit postmenopausal osteoporosis.


Assuntos
Densidade Óssea/efeitos dos fármacos , Reabsorção Óssea/prevenção & controle , Osso e Ossos/metabolismo , Glycine max/química , Isoflavonas/administração & dosagem , Osteoporose Pós-Menopausa/prevenção & controle , Biomarcadores/urina , Densidade Óssea/fisiologia , Reabsorção Óssea/etnologia , Brasil , Método Duplo-Cego , Feminino , Humanos , Isoflavonas/urina , Japão/etnologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/etnologia , Pós-Menopausa
15.
Osteoporos Int ; 12(1): 43-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11305082

RESUMO

Previous studies showed differences in bone and mineral metabolism in African-Americans and Caucasians: reductions in serum 25-hydroxyvitamin D [25(OH)D], urinary calcium and skeletal remodeling and moderate secondary hyperparathyroidism. Diurnal studies were carried out in 7 African-American and 7 white normal premenopausal women matched for age, weight and height to further characterize these racial differences in calcium homeostasis. Serum 25(OH)D was significantly lower and serum intact parathyroid hormone (PTH) was significantly higher in the African-American compared with the white women, whereas serum total calcium, Ca2+, phosphorus and 1,25-dihydroxyvitamin D [1,25(OH)2D] were not different in the two groups. Serum intact PTH increased significantly at night in the white women and did not change in the African-American women. Urinary calcium was 47% lower in the African-American than in the white women during the day but was not different at night. Urinary calcium declined at night by 53% in the white women and by 40% in the African-American women. Stepwise multivariate analysis showed that determinants of urinary calcium were mean 24 h serum intact PTH and serum Ca2+ in the two groups together, mean 24 h serum intact PTH, body mass index (BMI) and serum 25(OH)D in the white women, and BMI in the African-American women. Urinary N-telopeptide of type I collagen, a marker of bone resorption, increased by over 60% at night in both groups and was 25% lower in African-American compared with white women, but the difference was not statistically different. Urinary free deoxypyridinoline also increased at night in both groups and was not racially different. Thus, African-American women show higher serum intact PTH and greater conservation of calcium than white women throughout the day. In both groups, maintenance of serum calcium at night is achieved by increased bone resorption and renal conservation of calcium.


Assuntos
Reabsorção Óssea/etnologia , Cálcio/metabolismo , Ritmo Circadiano/fisiologia , Rim/metabolismo , Pré-Menopausa/fisiologia , Adulto , Antropometria , População Negra , Cálcio/sangue , Cálcio/urina , Feminino , Homeostase/fisiologia , Humanos , Análise Multivariada , Hormônio Paratireóideo/sangue , População Branca
16.
Osteoporos Int ; 11(6): 512-7, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10982167

RESUMO

Generally, the incidence of osteoporotic fracture is lower in black populations and in men. These effects of ethnicity and gender may result from differences in peak bone mineral density (PBMD) and bone turnover (BT), which in turn are affected by bone size. Therefore, the aims of this study were to examine the effects of ethnicity and gender on bone mineral density (BMD) and BT in young African-Caribbean and Caucasian adults, and to adjust for the effect of bone size on BMD and BT. BMD was measured at the lumbar spine, L2-L4 (LS), total body (TB) and femoral neck (FN) by dual-energy X-ray absorptiometry in 44 blacks (16 men, 28 women) and 59 whites (28 men, 31 women) ages 20-37 years. We measured serum bone-specific alkaline phosphatase (BAP) and serum osteocalcin (OC) as markers of bone formation and urinary immunoreactive free deoxypyridinoline (ifDpd) and crosslinked N-telopeptide of type I collagen (NTx) as markers of bone resorption. To adjust the data for any differences in bone size, we calculated: (a) bone mineral apparent density (BMAD), an estimated volumetric bone density which attempts to normalize BMD measurements for bone size; and (b) bone resorption markers as a ratio to total body bone mineral content (TB BMC). Two-way analysis of variance was used to compare the effects of race and gender, and to test for any interaction between these two factors. Blacks had higher BMD compared with whites at the TB (p<0.001), LS (p = 0.0001) and FN (p = 0.0005). This increase remained significant at the LS only after calculating BMAD. Men had higher BMD at all sites (except at the LS). This increase was no longer significant at the FN after calculating BMAD, and LS BMAD was actually greater in women (p<0.0001). Blacks and whites had similar concentrations of turnover markers, but men had higher bone turnover markers than women (BAP, p<0.0001; OC, p = 0.002; ifDpd, p = 0.03; NTx, p < 0.0001). This increase in bone resorption markers was no longer significant after adjusting for TB BMC (except for NTx in whites). We conclude that the skeletal advantage in blacks during young adulthood is not explained by bone size. However, it seems probable that bone size effects partially explain gender differences in BMD and bone turnover.


Assuntos
Densidade Óssea/fisiologia , Reabsorção Óssea/etnologia , Osteoporose/etnologia , Absorciometria de Fóton/métodos , Adulto , Fosfatase Alcalina/sangue , Aminoácidos/urina , População Negra , Remodelação Óssea/fisiologia , Reabsorção Óssea/metabolismo , Reabsorção Óssea/fisiopatologia , Colágeno/urina , Feminino , Humanos , Hidroxicolecalciferóis/sangue , Masculino , Osteocalcina/sangue , Osteoporose/fisiopatologia , Caracteres Sexuais , Tomografia Computadorizada por Raios X/métodos , População Branca
17.
J Lab Clin Med ; 127(1): 67-70, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8592098

RESUMO

Bone density is greater in blacks than in whites regardless of age. In adults, bone formation was shown previously to be much lower in blacks than in whites. A lower bone turnover in adult blacks may preserve a high bone density acquired earlier in life. Whether there is a difference in bone turnover in blacks and whites early in life is not known. Bone resorption is known to parallel bone formation, and thus in the present study we looked for racial differences in bone turnover in children by measuring the nocturnal urinary excretion of three markers of bone resorption: hydroxyproline and the pyridinium cross-links, pyridinoline and deoxypyridinoline. Sixty-four black and 145 white children ages 6 through 15 years were studied. We found excretion of hydroxyproline to be similar in whites and blacks. Urinary excretion of the cross-links was about 10% to 15% lower in blacks, but only the excretion of pyridinoline in boys was significantly lower in blacks (p = 0.031). Overnight urinary calcium excretion was about 30% lower in blacks than in whites (p = 0.0016 for boys and p = 0.008 for girls), as has been reported previously by others. In summary, the excretion rates of bone resorptive products in white and black children were similar, suggesting nearly equal bone turnover in the two racial groups, a finding that contrasts with observations made previously in adults.


Assuntos
População Negra , Reabsorção Óssea , Urina/química , População Branca , Adolescente , Aminoácidos/urina , Reabsorção Óssea/etnologia , Reabsorção Óssea/urina , Cálcio/urina , Criança , Feminino , Humanos , Estudos Longitudinais , Masculino , Potássio/urina
18.
J Clin Periodontol ; 16(10): 625-9, 1989 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-2613932

RESUMO

The prevalence of early periodontal destruction was assessed in a group of 516 14-year-old Iraqi schoolchildren who had not been offered public dental care programmes. Vertical bone loss adjacent to the proximal surfaces of first molars was used to indicate an incpient periodontal lesion, and the prevalence of subjects diagnosed as having one or more sites with this criterion in the Iraqi group was compared with those of 2 Scandinavian populations of the same age. These comprised 241 Norwegians who had received regular dental care and 561 Danes with or without such programmes. In the Iraqi group, 11.5% showed 1 or more sites with radiographic bone loss. However, few sites exhibited deep defects. There were significantly fewer Norwegian teenagers showing early periodontal lesions as compared to the Iraqi group (p less than 0.01) and the Danish subjects with no school dental programmes (p less than 0.01). Danish teenagers receiving regular dental care did not differ from the Norwegian group. It was concluded that the criterion used in the present study seems suitable for detecting differences in the prevalence of incipient radiographic periodontal lesions among young populations, and that the utilization of public dental care services may be an important factor in explaining such differences.


Assuntos
Reabsorção Óssea/epidemiologia , Assistência Odontológica , Etnicidade , Doenças Periodontais/epidemiologia , Adolescente , Reabsorção Óssea/diagnóstico por imagem , Reabsorção Óssea/etnologia , Criança , Dinamarca/epidemiologia , Feminino , Humanos , Iraque/epidemiologia , Masculino , Noruega/epidemiologia , Variações Dependentes do Observador , Doenças Periodontais/diagnóstico por imagem , Doenças Periodontais/etnologia , Prevalência , Radiografia , Fatores Sexuais
19.
J Clin Periodontol ; 15(2): 130-3, 1988 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3162245

RESUMO

The aim of the present study was to assess the prevalence of radiographic alveolar bone loss, as related to selected background variables in 2767 14-year old schoolchildren. Bone loss was recorded when the distance from the cemento-enamel junction to the alveolar crest exceeded 2 mm. The radiographs were magnified approximately 10 times. 3% of the subjects and 18.5% of the sites were excluded because of indistinct radiographic reference points. Radiographic bone loss was found in 4.5% of the subjects. Horizontal lesions were more prevalent than vertical defects. Most subjects with bone loss had 1 (75%) or 2 (22%) lesions. No subject was diagnosed with juvenile periodontitis kind of lesion. The prevalence of bone loss depended on the variables sex, orthodontic treatment and ethnic background.


Assuntos
Processo Alveolar/diagnóstico por imagem , Reabsorção Óssea/epidemiologia , Adolescente , Ásia/etnologia , Reabsorção Óssea/diagnóstico por imagem , Reabsorção Óssea/etnologia , Etnicidade , Feminino , Humanos , Masculino , Noruega/etnologia , Aparelhos Ortodônticos , Doenças Periodontais/diagnóstico por imagem , Doenças Periodontais/epidemiologia , Doenças Periodontais/etnologia , Radiografia , Suécia
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