Background Osteoporosis (OP) affects 8% of Spanish women, reaching to 23% when they are over 65 years old^1,2. The analysis of risk factors (RF) has high importance for the evaluation of patients with suspected OP.

Objectives To evaluate risk factors pattern for OP through the combination of those factors which increment more noteworthy its risk in postmenopausal women.

Methods We conducted a cross-sectional study with 3,049 postmenopausal women. They were sent for DXA at the lumbar spine (LS) to our Bone Densitometry of Rheumatology Unit, between 2010 and 2012. We include epidemiological characteristics (age, gender), RF for OP, location of fracture for adults, diseases and drugs that cause bone loss. We used an ordinal logistic regression to calculate Odds Ratios (ORs) and CI_95% for RF combinations, adjusted by: BMI, tobacco, alcohol, hip fracture on her mother, diagnoses and treatment.

Results In 42.9% of patients had osteopenia and in 25.6%, OP. Age average is 63.08±0.34 years old (median 62, rank 32-93). Descriptive statistics about RF show: 30.3% has BMI<25 or underweight (UW); 25% premature menopause (PM); and 31% previous fracture, among which osteoporotic one is the most common (19.8%). Between diseases that cause bone loss, 6.1% had any kind of chronic arthritis (rheumatoid arthritis, spondyloarthropathies or SLE) or collagenopathies (polymyalgia rheumatica, temporal arteritis, dermatomyositis), and 22.4% some other non-rheumatic disease.

In women with 55 or less years old (23.3%), only the combination between UW and OP previous fracture is a pattern of risk; OR: 2.17 (1.01-4.67).

In women between 56-65 years old (35.1%), UW, PM or osteoporotic previous fracture (OPfx) implies a risk increment between 51% and 96%. The combination of two of these RF raises the OP risk from two to three times: OR UW+PM: 3.12 (1.84-5.27); PM+OPfx: 2.74 (1.33-5.65); UW+OPfx: 2.30 (1.32-4.02). If a disease that cause bone lost is added, the baseline risk increase between 53% and 64%: OR 2.49 (1.31-4.76).

In women over 65 years (35.8%), to be underweight and to have a non-rheumatic disease increase the risk in 91%. The OR for the combination of UW+PM+fracture non-osteoporotic was 2.93 (1.36-6.31), and between UW+PM+OPfx: 2.64 (1.41-4.95)

Independently from the age, PM implies a risk from 1.52 when it combines with a non-osteoporotic previous fracture to 1.86, when it is combined with a UW. However, previous fracture plus a disease that cause bone loss raise the OP risk around 70%. To be UW joined other RF leads to the highest risks.

Conclusions

1. Analysis of RF for OP is useful to guide the disease risk. 2. Women underweight combined with other RF result in the highest OP risks. 3. The presence of two isolated RF increases the OP risk in 65% on average. 4. Three RF joined implies a risk average of 2.35, reaching 3.12 in women between 56-65 years old who are underweight and had premature menopause.

References

1. INE. INEBASE: Encuesta Nacional de Salud. Tablas nacionales, 2006.

2. Instituto de Mayores y Servicios Sociales (IMSERSO). Informe 2008. Las personas mayores en España. Datos estadísticos estatales y por CC.AA.

Disclosure of Interest None Declared