ORIGINAL PAPER
The association between bone mineral density and higher body mass index in men A. Oldroyd, S. Dubey
SUMMARY
What’s known
Background: A number of studies have identified that higher body mass index is associated with higher bone mineral density. However, a small number of previous studies have indicated an association between higher body mass index (> 35 kg/ m2) and lower bone mineral density. No previous study has investigated the association between higher body mass index and bone mineral density in a large male population. Methods: Data of men aged over 50 years of age who attended for a dual energy X-ray absorptiometry scan at a UK teaching hospital were collated. The population was divided according to body mass index increments of 5 kg/m2. The mean bone mineral density of both the lumbar spine and femoral neck was ascertained for each body mass index category. Multiple linear regression analysis, adjusted for age, was used to investigate for an association between body mass index and bone mineral density. Results: Data of 1263 men were collated. Increasing body mass index was associated with increasing bone mineral density of both the lumbar spine and femoral neck up to 35 kg/m2; further increase in body mass index was not associated with an increasing bone mineral density. Conclusions: The beneficial effect upon bone mineral density of increasing body mass index exists up to 35 kg/m2; a body mass index higher than 35 kg/m2 is not associated with further increase in bone mineral density.
Background Low bone mineral density (BMD) and resultant fragility fractures are a common cause of morbidity and mortality in the UK population and worldwide (1,2). With an aging population the prevalence of osteoporosis and the incidence of fragility fractures are predicted to increase (3,4). Also, the prevalence of UK individuals with a body mass index (BMI) higher than 30 kg/m2 is increasing and is predicted to increase further in the near future (5). A number of studies have investigated the relationship between BMD and BMI; these studies have consistently identified the association between low BMI (< 19 kg/m2), low BMD and an increased risk of sustaining a fragility fracture (6–8). A number of studies have identified that high BMI (25–30 kg/m2) is associated with higher levels of BMD, lower risk of osteoporosis and fragility fractures, compared to a normal BMI (19–25 kg/m2) (9–11); increased calcium intake and loading forces have been attributed to this association. Only a small number of studies have investigated the relationship between higher ª 2014 John Wiley & Sons Ltd Int J Clin Pract, January 2015, 69, 1, 145–147. doi: 10.1111/ijcp.12523
Increasing body mass index is associated with increasing bone mineral density. Higher body mass index in men may not be associated with further increases of bone mineral density.
What’s new Body mass index higher than 35 kg/m2 is not associated with further increase in bone mineral density in men aged over 50 years.
University Hospitals Coventry and Warwickshire, Coventry, UK Correspondence to: Dr Alexander Oldroyd, Department of Rheumatology, University Hospitals Coventry and Warwickshire, Clifford Bridge Road, Coventry, Warwickshire CV2 2DX, UK Tel.: + 07812 135 139 Fax: 02476966712 Email: [email protected]
Disclosure The authors have no conflicts of interest to disclose.
BMI (> 35 kg/m2) and BMD (12,13); these studies have suggested that a higher BMI does not confer further protection against osteoporosis and low BMD. Studies have predominantly investigated postmenopausal female populations. With the mean BMI of the male population at risk of osteoporosis and fragility fractures predicted to significantly increase in the next two decades, it is important to fully assess the relationship between higher BMI and BMD to ensure that prophylactic measures are being targeted appropriately.
Aim This study aims to investigate the association between higher BMI and BMD in a male population aged over 50 years.
Methods Data of men aged over 50 years that underwent a dual energy X-ray absorptiometry (DXA) scan at University Hospitals Coventry and Warwickshire
145
146
Bone mineral density and higher body mass index
(UK) between August 1991 and January 2014 were collated. The following variables were collated: age, BMI (kg/m2), mean lumbar spine (L1–L4) BMD (g/ cm2) and mean femoral neck BMD. The population was divided according to BMI categories of 5 kg/m2. The mean lumbar spine and femoral neck BMD for each BMI category was ascertained. Multiple linear regression, adjusted for age, was used to investigate for a relationship between age and BMD of the lumbar spine and femoral neck; this was firstly carried out for the whole population and secondly for the population with a BMI higher than 35 kg/m2.
Results Data for 1263 men were collated. Table 1 displays the baseline variables of the population. Table 2 displays the mean age, lumbar spine BMD and femoral neck BMD for each BMI category. An association between low BMI (15–20 kg/m2) and low BMD of both the lumbar spine and femoral neck was demonstrated – the lowest level of mean BMD of both the lumbar spine (0.84 g/cm2) and femoral neck (0.66 g/cm2) was in the low BMI (15– 20 kg/m2) categories. A positive association between BMD of both the lumbar spine and femoral neck and BMI was demonstrated; as confirmed by multiple linear regression modelling, adjusted for age: lumbar spine coefficient
Table 1 Baseline variables of population
Variable
Figure
Mean Mean Mean Mean
64.76 27.58 1.02 0.77
age/years (SD) BMI/kg/m2 (SD) lumbar spine BMD/g/cm2 (SD) femoral neck BMD/g/cm2 (SD)
(8.47) (4.81) (0.20) (0.14)
0.01 (p < 0.05), femoral neck coefficient 0.01 (p < 0.05). This positive association did not persist for BMI above 35 kg/m2; as confirmed by multiple linear regression modelling, adjusted for age and the presence of osteoporosis risk factors: lumbar spine coefficient < 0.01 (p = 0.98), femoral neck coefficient < 0.01 (p = 0.58).
Discussion This study aimed to investigate the association between higher BMI (> 35 kg/m2) and BMD in a male population aged over 50 years. This study demonstrated that the positive association between BMI and BMD does not persist above a BMI of 35 kg/m2. Increasing BMI above 35 kg/m2 is not associated with additional increase in BMD. These findings persisted following adjustment for the presence of osteoporosis risk factors. A small number of studies have investigated the association between higher BMI and BMD or osteoporosis. A study by Greco et al. (12) investigated the association between obesity (BMI > 25 kg/m2) and BMD in a population of 107 men; they found that a BMI higher than 30 kg/m2 was associated with low BMD, whereas a BMI of 25–30 kg/m2 was not associated with low BMD. A study by Ong et al. (14) analysed data of men and women from the Nottingham Fracture Liaison Service and found that a BMI higher than 35 kg/m2 conferred a higher positive predictive value for individuals not having osteoporosis, compared to a BMI between 30 and 35 kg/m2: 88.3% vs. 86.3%, respectively. A study by Barrera et al. (15) investigated the association between BMI and femoral neck osteoporosis in 230 men; they found that age-adjusted odds ratio for femoral neck osteoporosis was lower for men with a BMI 30– 35 kg/m2 (0.09 95% CI 0.01, 0.67), compared to men with a BMI 25–30 kg/m2 (0.13 95% CI 0.04, 0.43); this study did not investigate the association
Table 2 Mean BMI, age, lumbar spine BMD and femoral neck BMD for each BMI category of the male population
BMI category/kg/m2
Mean BMI/kg/m2
Mean age/years (SD)
Mean lumbar spine BMD/g/cm2 (SD)
Mean femoral neck BMD/g/cm2 (SD)
Number in category
15–20 20–25 25–30 30–35 35–40 40–45 > 45
18.45 23.09 27.35 32.04 36.79 41.37 50.81
64.92 65.35 64.76 64.71 62.56 61.19 63.80
0.84 0.96 1.03 1.10 1.12 1.11 1.10
0.66 0.71 0.78 0.83 0.86 0.90 0.88
37 352 530 258 63 16 5
(1.12) (1.40) (1.40) (1.37) (1.45) (1.56) (3.24)
(8.37) (9.07) (8.42) (8.02) (7.38) (7.04) (7.98)
(0.21) (0.18) (0.19) (0.20) (0.21) (0.16) (0.18)
(0.11) (0.11) (0.13) (0.14) (0.12) (0.16) (0.12)
ª 2014 John Wiley & Sons Ltd Int J Clin Pract, January 2015, 69, 1, 145–147
Bone mineral density and higher body mass index
between osteoporosis risk in men with a BMI higher than 35 kg/m2. No previous study has reported that increasing BMI above 35 kg/m2 is not associated with further increase in BMD. As described previously, the protective effect of obesity (BMI 25–30 kg/m2) upon osteoporosis and fragility fractures has been attributed to increased loading forces through long bones and increased level of calcium intake. Research has indicated that higher BMI (> 40 kg/m2) is associated with reduced levels of mobility and a more sedentary lifestyle and therefore lower loading forces through long bones (16); it may be that this is one reason for the association between higher BMI and BMD in this study. Studies have indicated that bone micro architecture consistent with fragility is associated with higher BMI and high level of body adiposity (17,18). It may be that the higher concentration of fat contained within bone in men with a BMI higher than 35 kg/m2 reduces BMD and weakens resilience of fracture against traumatic forces. The data used in this study was taken from a population that attended for a DXA scan for a clinical indication (e.g rheumatoid arthritis, long-term steroid use); the presence of these factors were not adjusted for in the analysis because of the absence of
References 1 Cummings SR, Melton LJ. Epidemiology and outcomes of osteoporotic fractures. Lancet 2002; 359: 1761–7. 2 Abrahamsen B, van Staa T, Ariely R, Olson M, Cooper C. Excess mortality following hip fracture: a systematic epidemiological review. Osteoporos Int 2009; 20: 1633–50. 3 Cooper C, Campion G, Melton LJ 3rd. Hip fractures in the elderly: a world-wide projection. Osteoporos Int 1992; 2: 285–9. 4 Gullberg B, Johnell O, Kanis JA. World-wide projections for hip fracture. Osteoporos Int 1997; 7: 407–13. 5 Wang YC, McPherson K, Marsh T, Gortmaker SL, Brown M. Health and economic burden of the projected obesity trends in the USA and the UK. Lancet 2011; 378: 815–25. 6 Joakimsen RM, Fonnebo V, Magnus JH, Tollan A, Sogaard AJ. The Tromso Study: body height, body mass index and fractures. Osteoporos Int 1998; 8: 436–42. 7 Roy DK, O’Neill TW, Finn JD et al. Determinants of incident vertebral fracture in men and women: results from the European Prospective Osteoporosis Study (EPOS). Osteoporos Int 2003; 14: 19–26.
ª 2014 John Wiley & Sons Ltd Int J Clin Pract, January 2015, 69, 1, 145–147
147
details on the indications (e.g duration and dose of steroid use). It may be that the presence of other osteoporosis risk factors is to explain for the observed relationship between BMI and BMD. Although this study has identified that higher BMI does not confer additional benefit upon BMD compared to high BMI, the risk of fragility fractures needs independent assessment in this group of patients. A small number of studies have been carried out into this topic, but more are required to reveal the likely complex relationship between BMD and higher BMI.
Conclusion BMD of both the lumbar spine and femoral neck increases with BMI. A BMI above 35 kg/m2 is not associated with further increases of BMD in men aged over 50 years.
Author contributions Dr Oldroyd collated, analysed and interpreted the results. Dr Dubey organised the collection of study data and result interpretation. The manuscript was jointly written by Dr Oldroyd and Dr Dubey.
8 De Laet C, Kanis JA, Oden A et al. Body mass index as a predictor of fracture risk: a meta-analysis. Osteoporos Int 2005; 16: 1330–8. 9 Felson DT, Zhang Y, Hannan MT, Anderson JJ. Effects of weight and body mass index on bone mineral density in men and women: the Framingham study. J Bone Miner Res 1993; 8: 567–73. 10 Ravn P, Cizza G, Bjarnason NH et al. Low body mass index is an important risk factor for low bone mass and increased bone loss in early postmenopausal women. Early Postmenopausal Intervention Cohort (EPIC) study group. J Bone Miner Res 1999; 14: 1622–7. 11 Reid IR, Ames R, Evans MC et al. Determinants of total body and regional bone mineral density in normal postmenopausal women–a key role for fat mass. J Clin Endocrinol Metab 1992; 75: 45–51. 12 Greco EA, Fornari R, Rossi F et al. Is obesity protective for osteoporosis? Evaluation of bone mineral density in individuals with high body mass index. Int J Clin Pract 2010; 64: 817–20. 13 Nielson CM, Srikanth P, Orwoll ES. Obesity and fracture in men and women: an epidemiologic perspective. J Bone Miner Res 2012; 27: 1–10. 14 Ong T, Sahota O, Tan W, Marshall L. A United Kingdom perspective on the relationship between body mass index (BMI) and bone health: a cross
sectional analysis of data from the Nottingham Fracture Liaison Service. Bone 2014; 59: 207–10. 15 Barrera G, Bunout D, Gattas V, de la Maza MP, Leiva L, Hirsch S. A high body mass index protects against femoral neck osteoporosis in healthy elderly subjects. Nutrition 2004; 20: 769–71. 16 Launer LJ, Harris T, Rumpel C, Madans J. Body mass index, weight change, and risk of mobility disability in middle-aged and older women. The epidemiologic follow-up study of NHANES I. JAMA 1994; 271: 1093–8. 17 Bredella MA, Lin E, Gerweck AV et al. Determinants of bone microarchitecture and mechanical properties in obese men. J Clin Endocrinol Metab 2012; 97: 4115–22. 18 Andersen S, Frederiksen KD, Hansen S, Brixen K, Gram J, Stoving RK. Bone structure and estimated bone strength in obese patients evaluated by high-resolution peripheral quantitative computed tomography. Calcif Tissue Int 2014; 95: 19–28.
Paper received May 2014, accepted July 2014
The association between bone mineral density and higher body mass index in men A. Oldroyd, S. Dubey
SUMMARY
What’s known
Background: A number of studies have identified that higher body mass index is associated with higher bone mineral density. However, a small number of previous studies have indicated an association between higher body mass index (> 35 kg/ m2) and lower bone mineral density. No previous study has investigated the association between higher body mass index and bone mineral density in a large male population. Methods: Data of men aged over 50 years of age who attended for a dual energy X-ray absorptiometry scan at a UK teaching hospital were collated. The population was divided according to body mass index increments of 5 kg/m2. The mean bone mineral density of both the lumbar spine and femoral neck was ascertained for each body mass index category. Multiple linear regression analysis, adjusted for age, was used to investigate for an association between body mass index and bone mineral density. Results: Data of 1263 men were collated. Increasing body mass index was associated with increasing bone mineral density of both the lumbar spine and femoral neck up to 35 kg/m2; further increase in body mass index was not associated with an increasing bone mineral density. Conclusions: The beneficial effect upon bone mineral density of increasing body mass index exists up to 35 kg/m2; a body mass index higher than 35 kg/m2 is not associated with further increase in bone mineral density.
Background Low bone mineral density (BMD) and resultant fragility fractures are a common cause of morbidity and mortality in the UK population and worldwide (1,2). With an aging population the prevalence of osteoporosis and the incidence of fragility fractures are predicted to increase (3,4). Also, the prevalence of UK individuals with a body mass index (BMI) higher than 30 kg/m2 is increasing and is predicted to increase further in the near future (5). A number of studies have investigated the relationship between BMD and BMI; these studies have consistently identified the association between low BMI (< 19 kg/m2), low BMD and an increased risk of sustaining a fragility fracture (6–8). A number of studies have identified that high BMI (25–30 kg/m2) is associated with higher levels of BMD, lower risk of osteoporosis and fragility fractures, compared to a normal BMI (19–25 kg/m2) (9–11); increased calcium intake and loading forces have been attributed to this association. Only a small number of studies have investigated the relationship between higher ª 2014 John Wiley & Sons Ltd Int J Clin Pract, January 2015, 69, 1, 145–147. doi: 10.1111/ijcp.12523
Increasing body mass index is associated with increasing bone mineral density. Higher body mass index in men may not be associated with further increases of bone mineral density.
What’s new Body mass index higher than 35 kg/m2 is not associated with further increase in bone mineral density in men aged over 50 years.
University Hospitals Coventry and Warwickshire, Coventry, UK Correspondence to: Dr Alexander Oldroyd, Department of Rheumatology, University Hospitals Coventry and Warwickshire, Clifford Bridge Road, Coventry, Warwickshire CV2 2DX, UK Tel.: + 07812 135 139 Fax: 02476966712 Email: [email protected]
Disclosure The authors have no conflicts of interest to disclose.
BMI (> 35 kg/m2) and BMD (12,13); these studies have suggested that a higher BMI does not confer further protection against osteoporosis and low BMD. Studies have predominantly investigated postmenopausal female populations. With the mean BMI of the male population at risk of osteoporosis and fragility fractures predicted to significantly increase in the next two decades, it is important to fully assess the relationship between higher BMI and BMD to ensure that prophylactic measures are being targeted appropriately.
Aim This study aims to investigate the association between higher BMI and BMD in a male population aged over 50 years.
Methods Data of men aged over 50 years that underwent a dual energy X-ray absorptiometry (DXA) scan at University Hospitals Coventry and Warwickshire
145
146
Bone mineral density and higher body mass index
(UK) between August 1991 and January 2014 were collated. The following variables were collated: age, BMI (kg/m2), mean lumbar spine (L1–L4) BMD (g/ cm2) and mean femoral neck BMD. The population was divided according to BMI categories of 5 kg/m2. The mean lumbar spine and femoral neck BMD for each BMI category was ascertained. Multiple linear regression, adjusted for age, was used to investigate for a relationship between age and BMD of the lumbar spine and femoral neck; this was firstly carried out for the whole population and secondly for the population with a BMI higher than 35 kg/m2.
Results Data for 1263 men were collated. Table 1 displays the baseline variables of the population. Table 2 displays the mean age, lumbar spine BMD and femoral neck BMD for each BMI category. An association between low BMI (15–20 kg/m2) and low BMD of both the lumbar spine and femoral neck was demonstrated – the lowest level of mean BMD of both the lumbar spine (0.84 g/cm2) and femoral neck (0.66 g/cm2) was in the low BMI (15– 20 kg/m2) categories. A positive association between BMD of both the lumbar spine and femoral neck and BMI was demonstrated; as confirmed by multiple linear regression modelling, adjusted for age: lumbar spine coefficient
Table 1 Baseline variables of population
Variable
Figure
Mean Mean Mean Mean
64.76 27.58 1.02 0.77
age/years (SD) BMI/kg/m2 (SD) lumbar spine BMD/g/cm2 (SD) femoral neck BMD/g/cm2 (SD)
(8.47) (4.81) (0.20) (0.14)
0.01 (p < 0.05), femoral neck coefficient 0.01 (p < 0.05). This positive association did not persist for BMI above 35 kg/m2; as confirmed by multiple linear regression modelling, adjusted for age and the presence of osteoporosis risk factors: lumbar spine coefficient < 0.01 (p = 0.98), femoral neck coefficient < 0.01 (p = 0.58).
Discussion This study aimed to investigate the association between higher BMI (> 35 kg/m2) and BMD in a male population aged over 50 years. This study demonstrated that the positive association between BMI and BMD does not persist above a BMI of 35 kg/m2. Increasing BMI above 35 kg/m2 is not associated with additional increase in BMD. These findings persisted following adjustment for the presence of osteoporosis risk factors. A small number of studies have investigated the association between higher BMI and BMD or osteoporosis. A study by Greco et al. (12) investigated the association between obesity (BMI > 25 kg/m2) and BMD in a population of 107 men; they found that a BMI higher than 30 kg/m2 was associated with low BMD, whereas a BMI of 25–30 kg/m2 was not associated with low BMD. A study by Ong et al. (14) analysed data of men and women from the Nottingham Fracture Liaison Service and found that a BMI higher than 35 kg/m2 conferred a higher positive predictive value for individuals not having osteoporosis, compared to a BMI between 30 and 35 kg/m2: 88.3% vs. 86.3%, respectively. A study by Barrera et al. (15) investigated the association between BMI and femoral neck osteoporosis in 230 men; they found that age-adjusted odds ratio for femoral neck osteoporosis was lower for men with a BMI 30– 35 kg/m2 (0.09 95% CI 0.01, 0.67), compared to men with a BMI 25–30 kg/m2 (0.13 95% CI 0.04, 0.43); this study did not investigate the association
Table 2 Mean BMI, age, lumbar spine BMD and femoral neck BMD for each BMI category of the male population
BMI category/kg/m2
Mean BMI/kg/m2
Mean age/years (SD)
Mean lumbar spine BMD/g/cm2 (SD)
Mean femoral neck BMD/g/cm2 (SD)
Number in category
15–20 20–25 25–30 30–35 35–40 40–45 > 45
18.45 23.09 27.35 32.04 36.79 41.37 50.81
64.92 65.35 64.76 64.71 62.56 61.19 63.80
0.84 0.96 1.03 1.10 1.12 1.11 1.10
0.66 0.71 0.78 0.83 0.86 0.90 0.88
37 352 530 258 63 16 5
(1.12) (1.40) (1.40) (1.37) (1.45) (1.56) (3.24)
(8.37) (9.07) (8.42) (8.02) (7.38) (7.04) (7.98)
(0.21) (0.18) (0.19) (0.20) (0.21) (0.16) (0.18)
(0.11) (0.11) (0.13) (0.14) (0.12) (0.16) (0.12)
ª 2014 John Wiley & Sons Ltd Int J Clin Pract, January 2015, 69, 1, 145–147
Bone mineral density and higher body mass index
between osteoporosis risk in men with a BMI higher than 35 kg/m2. No previous study has reported that increasing BMI above 35 kg/m2 is not associated with further increase in BMD. As described previously, the protective effect of obesity (BMI 25–30 kg/m2) upon osteoporosis and fragility fractures has been attributed to increased loading forces through long bones and increased level of calcium intake. Research has indicated that higher BMI (> 40 kg/m2) is associated with reduced levels of mobility and a more sedentary lifestyle and therefore lower loading forces through long bones (16); it may be that this is one reason for the association between higher BMI and BMD in this study. Studies have indicated that bone micro architecture consistent with fragility is associated with higher BMI and high level of body adiposity (17,18). It may be that the higher concentration of fat contained within bone in men with a BMI higher than 35 kg/m2 reduces BMD and weakens resilience of fracture against traumatic forces. The data used in this study was taken from a population that attended for a DXA scan for a clinical indication (e.g rheumatoid arthritis, long-term steroid use); the presence of these factors were not adjusted for in the analysis because of the absence of
References 1 Cummings SR, Melton LJ. Epidemiology and outcomes of osteoporotic fractures. Lancet 2002; 359: 1761–7. 2 Abrahamsen B, van Staa T, Ariely R, Olson M, Cooper C. Excess mortality following hip fracture: a systematic epidemiological review. Osteoporos Int 2009; 20: 1633–50. 3 Cooper C, Campion G, Melton LJ 3rd. Hip fractures in the elderly: a world-wide projection. Osteoporos Int 1992; 2: 285–9. 4 Gullberg B, Johnell O, Kanis JA. World-wide projections for hip fracture. Osteoporos Int 1997; 7: 407–13. 5 Wang YC, McPherson K, Marsh T, Gortmaker SL, Brown M. Health and economic burden of the projected obesity trends in the USA and the UK. Lancet 2011; 378: 815–25. 6 Joakimsen RM, Fonnebo V, Magnus JH, Tollan A, Sogaard AJ. The Tromso Study: body height, body mass index and fractures. Osteoporos Int 1998; 8: 436–42. 7 Roy DK, O’Neill TW, Finn JD et al. Determinants of incident vertebral fracture in men and women: results from the European Prospective Osteoporosis Study (EPOS). Osteoporos Int 2003; 14: 19–26.
ª 2014 John Wiley & Sons Ltd Int J Clin Pract, January 2015, 69, 1, 145–147
147
details on the indications (e.g duration and dose of steroid use). It may be that the presence of other osteoporosis risk factors is to explain for the observed relationship between BMI and BMD. Although this study has identified that higher BMI does not confer additional benefit upon BMD compared to high BMI, the risk of fragility fractures needs independent assessment in this group of patients. A small number of studies have been carried out into this topic, but more are required to reveal the likely complex relationship between BMD and higher BMI.
Conclusion BMD of both the lumbar spine and femoral neck increases with BMI. A BMI above 35 kg/m2 is not associated with further increases of BMD in men aged over 50 years.
Author contributions Dr Oldroyd collated, analysed and interpreted the results. Dr Dubey organised the collection of study data and result interpretation. The manuscript was jointly written by Dr Oldroyd and Dr Dubey.
8 De Laet C, Kanis JA, Oden A et al. Body mass index as a predictor of fracture risk: a meta-analysis. Osteoporos Int 2005; 16: 1330–8. 9 Felson DT, Zhang Y, Hannan MT, Anderson JJ. Effects of weight and body mass index on bone mineral density in men and women: the Framingham study. J Bone Miner Res 1993; 8: 567–73. 10 Ravn P, Cizza G, Bjarnason NH et al. Low body mass index is an important risk factor for low bone mass and increased bone loss in early postmenopausal women. Early Postmenopausal Intervention Cohort (EPIC) study group. J Bone Miner Res 1999; 14: 1622–7. 11 Reid IR, Ames R, Evans MC et al. Determinants of total body and regional bone mineral density in normal postmenopausal women–a key role for fat mass. J Clin Endocrinol Metab 1992; 75: 45–51. 12 Greco EA, Fornari R, Rossi F et al. Is obesity protective for osteoporosis? Evaluation of bone mineral density in individuals with high body mass index. Int J Clin Pract 2010; 64: 817–20. 13 Nielson CM, Srikanth P, Orwoll ES. Obesity and fracture in men and women: an epidemiologic perspective. J Bone Miner Res 2012; 27: 1–10. 14 Ong T, Sahota O, Tan W, Marshall L. A United Kingdom perspective on the relationship between body mass index (BMI) and bone health: a cross
sectional analysis of data from the Nottingham Fracture Liaison Service. Bone 2014; 59: 207–10. 15 Barrera G, Bunout D, Gattas V, de la Maza MP, Leiva L, Hirsch S. A high body mass index protects against femoral neck osteoporosis in healthy elderly subjects. Nutrition 2004; 20: 769–71. 16 Launer LJ, Harris T, Rumpel C, Madans J. Body mass index, weight change, and risk of mobility disability in middle-aged and older women. The epidemiologic follow-up study of NHANES I. JAMA 1994; 271: 1093–8. 17 Bredella MA, Lin E, Gerweck AV et al. Determinants of bone microarchitecture and mechanical properties in obese men. J Clin Endocrinol Metab 2012; 97: 4115–22. 18 Andersen S, Frederiksen KD, Hansen S, Brixen K, Gram J, Stoving RK. Bone structure and estimated bone strength in obese patients evaluated by high-resolution peripheral quantitative computed tomography. Calcif Tissue Int 2014; 95: 19–28.
Paper received May 2014, accepted July 2014
