osteoporosis and hip and vertebral osteoporotic fractures among an ageing population are a worldwide health problem that lead to a decreased quality of life ( 1 ) .
body weight and body mass index ( bmi ) are considered potentially modifiable determinants of bone mass ( 2 , 3 ) .
several studies have demonstrated an association of low body weight and bmi with low bmd and fractures ( 4 ) , while several other studies showed a protective effect of higher bmi on bmd ( 5 - 8 ) . among
most frequently cited mechanisms to explain this positive association of weight with bmd is weight - related loading on bones ( 9 ) , though higher estrogen and insulin synthesis and higher plasma leptin levels are considered to play an important role ( 10 ) . on the other hand
, it should be acknowledged that there are studies that did not demonstrate a significant positive association between weight and bmi and bmd or demonstrated a negative association of obesity and bmd ( 11 - 13 ) ; interaction between fat mass and bones through pro - inflammatory cytokines or low levels of adiponectins are some of the proposed mechanisms ( 14 - 16 ) .
the aim of this study was to explore the relationship between body weight and body mass index ( bmi ) with total hip and lumbar spine bone mineral density ( bmd ) in a population of 100 women and 32 men from kosovo .
sixty postmenopausal and forty premenopausal women , and thirty two men were prospectively enrolled in this cross - sectional study .
the study protocol was approved by the ethics committee , and written informed consent was obtained from all study participants before enrollment .
baseline anthropometric data ( height and weight ) were measured in light indoor clothing without shoes before performing dxa , and body mass index was calculated as kg / m .
the study population was classified in three categories on the basis of world health organization ( who ) body mass index ( bmi ) criteria : normal weight ( n=28 , bmi < 24.9 kg / m ) , overweight ( n=41 , 25.0 - 29.9 kg / m ) and obese ( n=63 , bmi>30 kg / m ) .
quantitative assessment of bone mineral density ( bmd ) at the lumbar spine and total hip was performed using dual - energy x - ray absorptiometry ( dxa ; stratos 800 ) technique by trained examiners .
the diagnosis of osteoporosis was done according to who t - score criteria ( osteoporosis was considered if t - score  -2.5 sd , low bone mass if t - score between -2.5 sd and -1 sd , and normal bmd if t - score > -1sd ) .
continuous variables are expressed as means  standard deviations ( median ) , while categorical data are presented as percentages .
as the data were not normally distributed , the kruskal - wallis test was used to compare characteristics of the groups , while chi square test was used for categorical variables
age - adjusted multiple linear regression analysis of independent associates ( weight and bmi ) of total lumbar spine and total hip bmd was calculated .
continuous variables are expressed as means  standard deviations ( median ) , while categorical data are presented as percentages .
as the data were not normally distributed , the kruskal - wallis test was used to compare characteristics of the groups , while chi square test was used for categorical variables
age - adjusted multiple linear regression analysis of independent associates ( weight and bmi ) of total lumbar spine and total hip bmd was calculated .
the study population consisted of 60 menopausal women with a mean age of 63.689.27 ( sd ) years , 40 premenopausal women with a mean age of 43.447.42 ( sd ) years and 32 men with mean age of 66.3414.97 ( sd ) years .
distribution of the total hip and total lumbar spine bmd according to bmi groups in menopausal and premenopausal women and men is presented in figure 1 .
the descriptive characteristics of the study population groups are shown in table 1 , which includes age , bmi , height , weight , lumbar spine and total bmd , as well as information regarding bmi groups and t - score groups .
there were no significant differences between study groups regarding body weight ( p=0.108 ) , while bmi score was significantly higher among menopausal women compared to premenopausal women or men ( p=0.001 ) .
there were no statistically significant differences in lumbar spine or total hip bmd values between three study groups .
there were significantly more obese and osteoporotic subjects among menopausal women compared to premenopausal women or men ( p<0.001 and p=0.002 , respectively ) .
distribution of total hip and lumbar spine bmd according to bmi groups descriptive characteristics of the study subjects .
parameters are given as mean standard deviation , median ( in the brackets ) , and number of cases ( percentage ) as appropriate ; a p - values of kruskal - wallis test or chi - square test as appropriate age - adjusted multiple linear regression analysis of independent associates of lumbar spine and total hip bmd .
bmd : bone mineral density , bmi : body mass index ,  : unstandardized regression coefficient a statistically significant difference was observed in menopausal women for both total hip and lumbar spine bmd values among bmi groups ( p=0.010 and p=0.003 , respectively ) .
total hip and lumbar spine bmd values in obese women at menopause were significantly higher compared to normal weight ( p=0.008 and p=0.035 , respectively ) .
lumbar spine bmd values in obese women at menopause were significantly higher compared to overweight women at menopause ( p=0.002 ) , while no statistically significant difference was observed in total hip bmd values between obese and overweight subjects ( p=0.061 ) .
no significant difference was observed between overweight and normal weight subjects in total hip and lumbar spine bmd values ( p=0.091 and p=0.783 , respectively ) .
age - adjusted multiple linear regression analysis showed that both weight and bmi were significant independent associates of lumbar spine and total hip bmd , with highest adjusted squared values in total hip bmd , where weight and bmi explained 37.1% and 37.2% of the variation , respectively .
a statistically significant difference was observed in premenopausal women for total hip bmd values among bmi groups ( p=0.023 ) .
total hip bmd values in obese premenopausal women were significantly higher compared to normal weight and overweight subjects ( p=0.007 and p=0.043 , respectively ) , while no statistically significant difference was observed in total hip bmd values between overweight and normal weight subjects ( p=0.458 ) .
no statistically significant difference was found for lumbar spine bmd values among bmi groups ( p=0.477 ) . according to age - adjusted multiple linear regression analysis no significant association of weight and bmi as independent variables with total hip and lumbar spine bmd
a statistically significant difference was observed in men for total hip bmd values among bmi groups ( p=0.007 ) .
total hip bmd values in obese male subjects were significantly higher compared to normal weight and overweight subjects ( p=0.03 and p=0.002 , respectively ) , while no statistically significant difference was observed in total hip bmd values between overweight and normal weight subjects ( p=0.938 ) .
no statistically significant difference was found for lumbar spine bmd values among bmi groups ( p=0.060 ) . nevertheless , age adjusted multiple linear regression analysis showed a significant positive effect of the bmi on lumbar spine bmd in men ( p=0.040 ) , where it explains 12.0% of the variation . though there was a positive tendency , no significant effect of weight
was observed on lumbar spine bmd in men ( p=0.058 ) , while both weight and bmi showed a significant positive effect on total hip bmd in men ( p=0.042 and p=0.028 , respectively ) according to multiple linear regression analysis .
in this cross - over study , we have demonstrated that total hip bmd levels of obese menopausal and premenopausal women and men were significantly higher compared to overweight or normal weight subjects , while lumbar spine bmd levels of only menopausal women and men were higher among obese subjects .
we also found evidence to suggest that bmi is a significant independent associate of lumbar spine and total hip bmd in both menopausal women and men .
every unit increase in bmi among menopausal women was associated with an increase of 0.1 g / cm2 in l1-l4 bmd , and 0.01 g / cm2 in total hip bmd , while among men every unit increase in bmi was associated with an increase of 0.012 g / cm2 in l1-l4 bmd , and 0.018 g / cm2 in total hip bmd .
our results are in agreement with some of the studies that demonstrated positive association of bmi with bmd . in this
regard , lloyd et al ( 5 ) examined variation in bmd across bmi spectrum using data from the national health and nutrition examination survey ( nhanes ) and found positive association of bmi with bmd in the respective sample of elderly subjects , without gender differences .
similarly , in a large retrospective cohort study in women aged 40 to 59 , morin et al ( 3 ) concluded that low weight and bmi predict osteoporosis and are associated with increased fracture risk .
our results are fully consistent with the results of doan et al ( 6 ) that conducted a similar study among 900 geriatric subjects and demonstrated a statistically significant difference for the lumbar spine and femur neck bmd levels among the bmi groups as well as a significant relationship between both the lumbar and the femoral bmd measurements and the bmi in women , and similarly found no significant differences in lumbar spine levels among bmi groups in men .
another recently conducted study of hoxha et al ( 7 ) in 64 males from kosovo compared bmi groups for l1-l4 bmd , femur neck bmd and total hip bmd levels , and reported no differences among them ; nevertheless , they demonstrated a positive correlation between bmi and femur neck and total hip bmd as well as positive association of bmi with all measurement sites bmd .
due to differences in the study populations , our results are partly consistent with them , as far as we found significant differences in total hip bmd values among bmi groups in men while we failed to demonstrate a significant association of bmi with lumbar spine bmd . on the other hand
, it should be acknowledged that there are studies that did not demonstrate a significant positive association between weight and bmi and bmd , or to the contrary demonstrated a negative association of obesity and bmd , thus seriously challenging the widespread belief that obesity is protective .
paniagua et al ( 11 ) found a high prevalence of osteopenia and osteoporosis among male nursing home residents who were more likely to be classified as overweight and obese according to bmi .
similarly , greco et al ( 12 ) demonstrated that obesity was associated with a osteoporosis and provided clinical evidence that obesity should not be considered as a protective factor .
in conclusion , total hip bmd values in obese menopausal and premenopausal women as well as men were significantly higher compared to overweight or normal weight subjects .
bmi was shown to be a significant independent associate of lumbar spine and total hip bmd in both menopausal women and men , while such a relationship among premenopausal women did not exist .
nevertheless , significantly more obese and osteoporotic subjects among menopausal women represent a population at risk for fractures because of poor balance and frequent falls ; therefore , both obesity and osteoporosis prevention efforts should begin early on in life .
 background and objective : body weight and body mass index ( bmi ) are considered potentially modifiable determinants of bone mass . 
 therefore , the aim of this study was to explore the association between body weight and body mass index ( bmi ) with total hip and lumbar spine bone mineral density ( bmd).methods : this cross - sectional study included a population of 100 women and 32 men from kosovo into three bmi groups . 
 all the study subjects underwent dual - energy x - ray absorptiometry ( dxa ) measurements.results:total hip bmd levels of obese menopausal and premenopausal women and men were significantly higher compared to overweight or normal weight subjects , while lumbar spine bmd levels of only menopausal women and men were higher among obese subjects . 
 age - adjusted linear regression analysis showed that bmi is a significant independent associate of lumbar spine and total hip bmd in menopausal women and men.conclusion:despite positive association between bmi and lumbar spine and total hip bmd in menopausal women , presence of more obese and osteoporotic subjects among menopausal women represent a population at risk for fractures because of poor balance and frequent falls ; therefore , both obesity and osteoporosis prevention efforts should begin early on in life . 
1. INTRODUCTION
2. MATERIAL AND METHODS
Statistical analysis
3. RESULTS
4. DISCUSSION
5. CONCLUSION