Prevalence of Osteoporosis in General Population above 50 Yrs of Age

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1 International Journal of Advances in Health Sciences (IJHS) ISSN Vol 3, Issue 2, 2016, pp Research Article Prevalence of Osteoporosis in General Population above 50 Yrs of Age Moudgil V, Virk OS and Boparai RS PIMS ABSTRACT Osteoporosis is currently a public health problem of major concern in Indiawhich leads to increased susceptibility to fracture. The condition clinically manifest in the form of generalized body ache, hip fracture, distal radius fracture or vertebral fractures. The level of peak bone mass is achieved by early adulthood and thereafter there is a progressive loss of bone density, roughly estimated to be around 1 per cent per year. Bone mineral density (BMD) is strongly influenced by body weight, Vitamin D levels, hormone replacement therapy sedentary life style, chronic liver disease, endocrinal disorders, smoking, excessive alcohol and caffeine intake. Dual energy X-ray absorptiometry (DEXA) is the gold standard for diagnosing osteoporosis by measuring bone density, AIMS AND OBJECTIVE The study intends to know the prevalence, distribution of osteoporosis by measurement of bone mineral density using Dual energy X-ray absorptiometry (DEXA) at L1-L5 vertebrae METHOD: This is a prospective study in which 250 patients above 50 year of age were selected who presented with generalized body ache, backache and patients who were willing to be part of study. All patients underwent DEXA scan for estimation of bone mineral density at L1-L5 vertebrae. RESULTS:In our study 176 patients were females and 74 male. 147(58.8%) patients were aged between years, 79(31.6%) patients were aged between years and 24(9.6%) were above 70 years. Mean age in study was 59.6 years with age ranging from 50yrs to 81.6 years. Mean height and weight was cms and 65.46kgs respectively. Mean BMD was found to be lower in patients aged >70. Mean T score and Z score was and respectively. Over all Prevalence of osteoporosis was found to be 27.2%, and that of osteopenia was 41.6%. CONCLUSION : Both sexes are equally at risk of developing osteoporosis. Risk of developing osteoporosis increases with increasing age. BMD is less in females compared to males. One of the important determinants of bone health is BMI which is directly proportional to BMD.The findings from the study suggest the need for large community-based studies so that high-risk population can be picked up and early interventions and other life style changes can be instituted. KEYWORDS: Bone mineral density, DEXA, Osteoporosis,lumbar Spine, Femur head, postmenopausal women INTRODUCTION Osteoporosis is an established and well-defined disease that affects more than 51% of population above 50 years of age. According to national census about 163 million Indians over age 50 are affected with osteoporosis a number expected to increase to 230 million by Prevention of the disease and its associated fractures is essential for maintaining health, quality of life, and independence among the elderly. 2 Osteoporosis is defined as bone mineral density that is less than 2.5SD below the mean peak value in young adults of the same race and sex (t score of 2.5). 3 An estimated million hip fractures occurred worldwide in By 2025, this number is expected to increase to almost 3 million. BONE DENSITOMETRY: Number of techniques are now available to measure the bone mass at various skeletal sites. The values obtained from these measurements represent the bone mineral density (BMD). Single and dual X-ray absorptiometry (SXA, DXA) are methods of assessing the mineral content of the whole skeleton, as well as of specific sites, including those most vulnerable to fracture. 4 The term bone mineral content describes the amount of mineral in the specific bone site scanned, from

2 which a value for BMD can be derived by dividing the bone mineral content by the area or volume measured. With both SXA and DXA this is an areal density rather than a true volumetric density, since the scan is twodimensional. In single-energy absorptiometry, bone mineral is measured at appendicular sites, such as the heel or wrist. SXA is widely available for forearm mineral measurements, and is more precise than single photon absorptiometry (SPA), which also has the disadvantage of requiring the use of isotopes such as 156I. 5 Dual-energy absorptiometry measures bone mineral at sites such as the spine and hip; it can also measure total body bone mineral. SPA and SXA cannot be used for these sites. DXA is also being increasingly used for measurements at appendicular sites. DXA is regarded as the gold standard Ultrasound: Broad-band ultrasound attenuation (BUA) and speed of sound (SOS) or ultrasound velocity at the heelhas been used to assess skeletal status in osteoporosis. These methods have the advantage in that they do not involve ionizing radiation and may provide information on the structural organization of bone in addition to bone mass. Computed tomography: Quantitative computed tomography (QCT) has been applied both to the appendicular skeleton and to the spine 6-7. Cancellous bone in the spine and radius is highly suitable for assessment by QCT. Radiography: Osteoporosis can often be diagnosed by visual inspection of plain radiographs, albeit with low sensitivity. A decrease in the apparent density of bone detected radio graphically is not specific for osteoporosis and is more appropriately termed osteopenia. Magnetic resonance imaging (MRI) provides no direct information on density, but with the positive background given by all types of bone marrow, it provides some resolution of the internal structure of cancellous bone. 8 At present, MRI investigation of the skeleton remains a research procedure because of its high costs and complexity. Biochemical assessment of fracture risk Biochemical markers of bone turnover may be divided into two groups, namely markers of bone resorption and markers of bone formation 8. Diagnosis The most straightforward approach to the diagnosis of osteoporosis by bone density measurements is to define a threshold, namely a cut-off point for BMD that will encompass most patients with osteoporotic fractures. Bone density measurements are, however, also used to assess future risk of fracture, so that more than one threshold will be needed. Thresholds: Skeletal mass and density remain relatively constant once growth has ceased, until approximately age 50 years in females and 65 years in males. 9 The distribution of bone mineral content or density in young healthy adults (peak bone mass) is approximately normal irrespective of the measurement technique used. With this distribution, individual bone density values are expressed in relation to a reference population in standard deviation units. This reduces the effects of differences in calibration between instruments. Standard deviation units used in relation to the young healthy population are called T-scores. The following four general diagnostic categories have been proposed by a WHO based on measurements by DXA 10 Normal - BMD within 1 standard deviation of the young adult reference means (T-score -1). Osteopenia - A value of BMD more than 1 standard deviation below the young adult mean, but less than 2 standard deviations below this value (T-score < -1 and > -2.5). Osteoporosis - A value of BMD 2.5 standard deviations or more below the young adult mean (T-score -2.5). Severe osteoporosis (established osteoporosis) - BMD 2.5 standard deviations or more below the young adult mean in the presence of one or more fragility fractures. In women, bone loss occurs predominantly after the menopause. In the young healthy population, about 15% of women will have T scores less than -1 and thus meet the criteria for low bone mass or osteopenia. By this definition, approximately 0.6% of the young healthy population has T-scores of -2.5 or less and thus has osteoporosis. Moudgil V, et al. 80

3 TYPES OF OSTEOPOROSIS TYPE 1 OSTEOPOROSIS (POSTMENOPAUSAL) : It affects trabecular bone primarily. Vertebral and distal radius fractures are common in these women. Mainly due to Oestrogen deficiency which accelerates the rate of bone turnover, thereby altering the balance between bone formation and bone resorption TYPE II OSTEOPOROSIS (SENILE): Seen in patients older than 75 years. This affects both cortical and trabecular bone. Hip and pelvic fractures are common in these women. SECONDARY CAUSES OF OSTEOPOROSIS 11 Genetic disorders (ehlers-danlos syndrome, glycogen storage disease), Gastrointestinal diseases (inflammatory bowel disease, coeliac disease), Hypogonadal states (androgen insensitivity, Turner s syndrome), Rheumatological diseases, Endocrine disorders (acromegaly, thyroid disease, DM), Haematological disorders (multiple myeloma, sickle cell disease), Drugs (anticoagulants alcoholism anticonvulsants), parenteral nutrition amyloidosis and immobilization Diagnostic work up The same diagnostic approach would be adopted in all patients with osteoporosis irrespective of the presence or absence of fragility fractures. The range of clinical and biological tests used to assess osteoporosis will depend on the severity of the disease, the age at presentation, the presence or absence of vertebral fractures, and the reason for the assessment, which may be to: - exclude a disease which can mimic osteoporosis; - elucidate the causes of osteoporosis and the contributory factors - assess the severity of osteoporosis and thus to determine the risk of subsequent fractures; - select the most appropriate treatment; - establish baseline measurements for subsequent monitoring of treatment. - Diagnostic procedures are used to investigate osteoporosis. - establish the diagnosis of osteoporosis (e.g. DXA or X-rays); - establish the cause (e.g. thyroid function tests for hyperthyroidism, and urinary free cortisol for Cushing syndrome); - Establish the differential diagnosis (e.g. protein electrophoresis for myeloma, and serum calcium and alkaline phosphatase for osteomalacia). Investigations commonly carried out in specialized centres include determination of the biochemical indices of bone turnover, serum PTH, and serum 1a,25- dihydroxycholecalciferol, serum or urine protein electrophoresis, measurement of fasting and 24- hour urinary calcium, and urinary free cortisol, and thyroid function tests and trans iliac bone biopsy Newer method to assess fracture risk 12 The FRAX tool has been developed by WHO to evaluate fracture risk of patients. It is computer based software, individual patient models that integrate the risks associated with clinical risk factors as well as bone mineral density (BMD) at the femoral neck. The FRAX models have been developed from studying population-based cohorts from Europe, North America, Asia and Australia. The FRAX algorithms give the 10- year probability of fracture. The output is a 10- year probability of hip fracture and the 10-year probability of a major osteoporotic fracture (clinical spine, forearm, hip or shoulder fracture. A 10-year probability of fracture was preferred to lifetime risks, because (1) assumptions on future mortality introduce increasing uncertainties for risk assessment beyond 10 years; (2) treatments are not generally given feasibly over a lifetime; (3) the long-term prognostic value of some risk factors may decrease with time; and (4) the 10-year interval accommodates clinical trial experience of interventions (generally3 5 years) and the reversal phase (offset time) when treatment is stopped. Risk factors included in FRAX. The FRAX tool takes T-score into account and other osteoporosis risk factors: Age, Height and weight, Smoking, Alcohol consumption, Other health conditions, such as rheumatoid arthritis, Corticosteroid use, Family history of fractures, Personal history of fractures. Moudgil V, et al. 81

4 Aim of the study was to estimate the prevalence and distribution of osteoporosis by measurement of bone mineral density using Dual energy X- ray absorptiometry (DEXA) at L1-L5 vertebrae in patients above 50 years of age MATERIAL and METHODS DESIGN OF STUDY It was a prospective study done at Punjab Institute of Medical Sciences; Jalandhar.250 patients above 50 years of age who presented to outpatient department with generalized body ache or back ache were randomly selected and included in study. All patients underwent DEXA scan. Study was performed from March 2014 to March METHOD OF COLLECTION OF DATA After careful history taking and examination patient details and examination finding were filled in pre designed proforma. Personal information including age, sex, height, weight, BMI, BMD, T-score and Z-score was recorded. Patients below 50 years and osteoporosis due to secondary cause e.g. tuberculosis, malignancy etc. were excluded All patients included in study underwent DEXA SCAN Values of bone mass density at L1-L5 vertebrae was measured and T score and Z score was calculated T score = Measurement value-young adult mean Young adult population SD Z score =Measurement value-age-matched mean Age-matched population SD T-SCORE DEXA test results were compared to the ideal or peak bone mineral density of a healthy 30-yearold adult, and T-score was calculated. Differences between BMD and that of the healthy young adult norm were measured as standard deviations (SDs). The more standard deviations below 0 indicated as negative numbers, the lower the BMD and the higher your risk of fracture. Z-SCORE Bone mineral density was compared to that of a typical individual whose age is matched and Z- score calculated. Because a low BMD level is common among older adults, comparisons with the BMD of a typical individual whose age is matched can be misleading. Therefore, the diagnosis of osteoporosis or low bone mass is based on T- score. However, a Z-score can be useful for determining whether an underlying disease or condition is causing bone loss. It is most useful when the score is less than 2 standard deviations below the normal. It suggests coexisting illnesses that may contribute to osteoporosis such as glucocorticoid therapy, hyperparathyroidism or alcoholism. FRACTURE RISK Fracture risk in study was calculated using FRAX score. Correlation between age, sex, and fracture risk, bone mass density (BMD) and body mass index (BMI) was done using p value, chi square test and PEARSONS CORRELATION COEFFICIENT. RESULTS: The study group comprised of 250 patients. Out of 250 patients 176 (70.4%) were females and 74 (29.6%) were males.the age of the patient ranged from 50 to 84 years with mean of years (Table no. 1). Mean height and weight was cms and 65.4kgs respectively. Height ranged from 141 to 186cms and weight ranging from 43kgs to 100kgs. Mean BMD and BMI was and Based on BMD values out of 250 patients, 68(27.2%) were found to be osteoporotic, 104(41.6%) patients were having osteopenia and 78(31.2%) patients showed normal values. Effect of age:out of 250 patients, in the normal group 52(66.67% ) patients were in age group of years, 22(28.2%) were in age group of years age group and 4 (5.12%) were in> 70 year age group. In osteopenic group 62(41.5%) were in year age group, 31(39.2%) were in age group of age group and 11(45.8%) in>70 year age group. In osteoporosis group,33(22.4%)were in years age group, 26 (32.9 %)were in age group and 9(37.5%) were in>70 year age group(table No. 2) Effect of gender:females 48(27.3%) were normal, 78(44.3%) were osteopenic and 50 Moudgil V, et al. 82

5 (28.3%) were osteoporotic. In males 30 (40.5%) were normal, 26 (35.1%) were osteopenic and 18(24.3%) were osteoporotic. (Table No. 3) FRAX score 10 year fracture risk in study group using FRAX score was calculated to be 62 (24.8%) had high risk 110 (44%)had moderate risk and78 (31.2 %)had low risk. Age group FRACTURE RISK according to age: years there were 147 patients 29(19.7%) had high risk,53(36.1%) had low risk and 65(44.2%) had moderate risk years there were 79 patients, 23(29.1%) had high risk, 22(27.8%) had low risk and 34(43%) had moderate risk. >70 years there were 24 patients, 08(33.3%) had high risk, 05(20.8%) had low risk and 11(45.8%) had moderate risk. (Table no.4-5). T score and Z score: Mean T-score was and Mean Z-score was In age groups, 50-59yearsMean T-Score was and Mean Z-Score was In age groups, years Mean T-Score was and Mean Z-Score was In age groups, >70 years Mean T-Score was and Mean Z- Score was ( Table No. 6-7). In females mean T-score was and Z-Score was In males mean T-score was and Z-Score was (Table no.8) Effect of BMI: Mean BMI was and mean BMD was In year age group mean BMI was 19.4 and mean BMD was year age group mean BMI was 18.3 and mean BMD was and >70 year age group mean BMI was 17.4 and mean BMD was (Table No.6-7). In females mean BMI was 18.3 and BMD was In males mean BMI was 19.4 and BMD was (Table no.8) Tests of Significance: In comparison of p value using chi square (p value <0.05 is considered significant) Comparison of age and fracture risk: Pearson Chi-Square value for 250 cases 5.00; p=0.287 Comparison of gender and fracture risk: Pearson Chi-Square value for 250 cases 5.138; p=0.077 None of the comparison between age and gender with fracture risk was significant. PEARSONS CORRELATIONof indicates correlation and is significant between BMI and BMD. DISCUSSION: Osteoporosis is the most common generalized disease of the skeleton and with progressive ageing of the world s population, the proportion ofwomen with osteoporosis is expected to increase further. Osteoporosis is defined by the World Health Organization (WHO) as a bone mineral density of 2.5 standard deviations or more below the mean peak bone mass (average of young, healthy adults) as measured by dual-energy X- ray absorptiometry; the term "established osteoporosis" includes the presence of a fragility fracture. Several large prospective studies have confirmed that for each SD decline in BMD there is an increase in fracture risk 1314 In our study of 250 patients aged above 50 years there were 176(70.4%) female patients and 74(29.6%) males. There were highest patients in age group of age groups. 147(58.8%) patients were aged between years, 79(31.6%) patients were aged between years and 24(9.6%) were above 70 years.mean age in study was 59.6 years with age ranging from 50yrs to 81.6 years. Mean height and weight was cms and 65.46kgs respectively. Mean BMD was found to be lower in patients aged>70.mean T score and Z score was and respectively. Over all prevalence of osteoporosis was found to be 27.2%, and that of osteopenia was 41.6%. Positive correlation was found between BMI and BMD i.e. Patients with lower BMI had lower BMD. Fracture risk was found to be low in 80(31.2%), moderate in 110(44%) and high in 60(24.8%) based on DEXA scan findings. Age wise prevalence of osteoporosis increased with increasing age. Though the number of patients above 70 years was less(24) but prevalence of osteoporosis was more 33.3%.Whereas in age group of years it was 19.7% and 29.1% in years group. In our study there was no significant difference found between fracture risk and sex. High fracture risk was 24.4% & 23.0% respectively in males and females. Prevalence of osteoporosis and osteopenia obtained in our study group was compared with study done by Mithal A and Moudgil V, et al. 83

6 Bansal B et al 15.A study among Indian population aged 40-70years, bone mineral density (BMD) at all skeletal sites was much lower than values reported from developed countries, with a high prevalence of osteopenia (42%) and osteoporosis (29%) Study Osteopenia Osteoporosis Ambrish Mitha et al 42% 29% Tarek Fowzy et al 35.6% 25.7% Our study 44% 24% Mean BMD was found to be lower in age group above 60 years ina study done by Fowzy T et al 16. The mean BMD was low in 88.2% patients aged above 60 years. In our study also mean BMD of patients above 60 years was found to be low in 85.3% as compared to patients in years age group. Study 50-60years >60 years Tarek Fowzy et al 60.9% 88.2 % Our study 63.9% 85.3% Salamat M Retal 17 also found correlation between BMI and BMD at L1-L5 vertebrae. According to his study over weight decreased the risk for osteoporosis.bmi was lower in patients with low BMD. In our study also we found that mean BMI was lower in patients with lower BMD.Similarly results were also found in study by Fowzy T 17. The Studies of National Osteoporosis Foundation and others suggested that low BMI should be included in the risk assessment tools for evaluation of osteoporosis and osteoporotic fracture risk CONCLUSION: In our study of 250 patients above 50 years of age with bone pain the prevalence of Osteoporosis was 27.2% and osteopenia was 41.2%. Risk of osteoporosis and developing fracture increases with age. Both sex are equally at risk of developing osteoporosis with increasing age. BMD in females is less as compared to males. One of the important determinants of bone health is BMI, which is directly proportional to BMD. The findings from the study suggest the need for large community based studies so that high risk population can be picked up and early interventions and other life style changes can be instituted. Sources of financial support: none TABLES TABLE NO. 1 Showing the age wise distribution of patients AGE (yrs) NO. OF PATIENTS PERCENTAGE (%) > Total Table No. 2 Showing the age wise distribution of Osteopenia and Osteoporosis Crosstab AGE >70 yrs Count NORMAL % within age 35.4% 27.8% 16.7% 31.2% Count OSTEOPENIA % within age 41.5% 39.2% 45.8% 41.6% RESULT Count OSTEOPOROSIS % within age 22.4% 32.9% 37.5% 27.2% Count % within age 100% 100% 100% 100% Table No.3 Chart showing the sex wise distribution of osteoporosis and osteopenia Crosstab SEX FEMALE MALE Count NORMAL RESULT %within sex 27.3% 40.5% 31.2% Moudgil V, et al. 84

7 OSTEOPENIA OSTEOPOROSIS Count %within sex 44.3% 35.1% 41.6% Count % within sex 28.4% 24.3% 27.2% Count % within sex 100% 100% 100% Table No. 4 Showing age wise distribution of fracture risk Crosstab AGE >70 yrs HIGH Count % 19.7% 29.1% 33.3% 24% Count LOW FRACTURE % 36.1% 27.8% 20.8% 32% RISK Count MODERATE % 44.2% 43% 45.8% 44% Count % 100% 100% 100% 100% Table No. 5 Showing sex wise distribution of fracture risk Crosstab SEX FEMALE MALE HIGH Count % 24.4% 23% 24% Count MODERATE FRACTURE % 47.7% 35.1% 44% RISK Count LOW % 27.8% 41.9% 32% Count % 100% 100% 100% Table No. 6 Showing the mean, standard deviation,minimum and maximum values of age, height, weight, BMD, BMI, T-score and Z-score STATISTICS AGE HEIGHT WEIGHT BMI BMD T-SCORE Z-SCORE N Valid Mean St. Deviation Minimum Maximum Table No.7 Showing the mean and standard deviation of height, weight, BMD,T-score and Z-score in each age group AGE yrs yrs >70yrs Mean Standard Mean Standard Mean Standard HEIGHT(cms) WEIGHT(kg) BMI BMD T-SCORE Z-SCORE Table no. 8 Showing the mean and standard deviation of height, weight, BMD,T-score and Z-score FEMALE MALE Mean Standard Mean Standard Moudgil V, et al. 85

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