The Global Burden Attributable to Low Bone Mineral Density

Abstract

INTRODUCTION: Osteoporosis and osteoporotic fractures represent an enormous health burden and economic cost for most societies in the world, and future projections forecast their steady increase over the next few decades. Strategies to detect and treat those individuals with high risk of fracture have proved to be cost-effective, but still an important lack of awareness exists among health professionals and institutions. Low bone mineral density (BMD) is one of the factors better correlated with fracture risk. The Global Burden of Disease Study 2010 estimated the worldwide health burden of 291 diseases and injuries and 67 risk factors. The main metrics for the burden measurements were the Disability-Adjusted Life Years (DALYs), the Years lived with disability (YLDs), the Years of Life Lost due to premature mortality (YLLs) and Deaths. For the first time, BMD was analysed as a risk factor for fractures, which formed part of the health burden due to falls. Risk analysis followed the Comparative Risk Assessment (CRA) methodology to determine which proportion of the falls burden was attributable to low BMD.

OBJECTIVES: To calculate the global distribution of BMD, its population attributable fraction (PAF) for falls, and the number of DALYs, YLDs, YLLs and deaths due to low BMD, with estimates for each region, age group, sex and time period (1990 and 2010).

METHODS: Systematic review was performed seeking population-based studies with BMD measured by Dual-X-Ray-Absorptiometry at femoral neck in people 50 years and over. Age- and sex- specific levels of mean BMD+/-SD (g/cm2) were extracted from eligible studies. For the CRA methodology to calculate PAFs of BMD for fractures, the theoretical minimum risk factor exposure distribution was estimated as the age and sex-specific 90th percentile from NHANES III. Relative risks for fractures were obtained from a previous meta-analysis. Hospital data with double coding (cause and nature of injury) was used to calculate the fraction of the health burden of falls due to fractures.

RESULTS: Global deaths and DALYs attributable to low BMD increased from 103,000 and 3,125,000 in 1990 to 188,000 and 5,216,000 in 2010 respectively. The contribution to the total DALYs was slightly superior for YLLs compared to YLDs. The percentage of low BMD in the total global burden almost doubled from 1990 (0.12%) to 2010 (0.21%). In population 70 years old and over these percentages increased from 0.64% in 1990 to 0.79% in 2010. Around one third of all falls-related deaths were attributable to low BMD, with slight increase between 1990 and 2010. Low BMD was responsible for 12.1% and 14.8% of all global DALYs due to falls in 1990 and 2010, respectively. Males showed more contribution to the global deaths and DALYs, with a higher increase over time, compared to females. Asia South and Asia East were the world regions contributing the most in the increase of the global burden attributable to low BMD over time. The greatest proportion of DALYs within the regional burden was found in Europe Western, Europe Central and Asia Pacific-High Income. Low BMD was the eight risk factor with the highest number of global YLDs in population 80 years and over.

CONCLUSION: Results showed an increase of the burden attributable to low BMD worldwide from 1990 to 2010, greatly influenced by the ageing of the population. A significant fraction of all falls-related deaths and health burden in the world was attributable to low BMD and, therefore, preventable. Data systems should improve in the detection of injuries potentially related to low BMD and osteoporosis in general. This information can be used by health institutions and authorities to identify priorities and allocate resources.

INTRODUCCIÓN: En la iniciativa The Global Burden of Disease Study 2010, la densidad mineral ósea (DMO) ha sido analizada como un factor de riesgo de fracturas, las cuales son analizadas como parte de la carga en salud atribuida a las caídas. Las medidas métricas principales para determinar la carga en salud de dicha iniciativa son los Disability-Adjusted Life Years (DALYs), los Years lived with disability (YLDs), los Years of Life Lost due to premature mortality (YLLs), y las Muertes.

OBJETIVOS: Calcular la distribución mundial de los valores de DMO; calcular el número de DALYs, YLDs, YLLs y muertes debidos a la baja DMO.

MÉTODOS: Se realizó una revisión sistémica de estudios poblacionales con valores de DMO medidos con Dual-X-Ray-Absorptiometry en cuello femoral en población a partir de 50 años. Se utilizó análisis de riesgo comparativo para determinar la fracción poblacional atribuible de la DMO para caídas. El percentil 90 por grupo de edad y género del estudio americano NHANESIII se adquirió como la distribución de mínimo riesgo posible del factor de exposición. Los riesgos relativos DMO-fractura se obtuvieron de una meta-análisis previa. Datos hospitalarios con doble codificación (causa y tipo de lesión) se utilizaron para calcular la fracción de la carga en salud de las caídas debido a las fracturas.

RESULTADOS: Las muertes y los DALYs mundiales atribuibles a la baja DMO incrementaron de 103.000 y 3.125.000 en 1990 a 188.000 y 5.216.000 en 2010, respectivamente. Un tercio de todas las muertes relacionadas con caídas fueron atribuibles a la baja DMO. La DMO fue responsable de un 12.1% y un 14.8% de todos los DALYs por caídas en 1990 y 2010, respectivamente. El Asia Sur y Asia Este fueron las regiones del mundo que más contribuyeron al aumento de la carga mundial en salud atribuible a la baja DMO.

CONCLUSIÓN: Los resultados muestran un aumento de la carga en salud mundial debido a la bajo DMO entre 1990 y 2010. Una séptima parte de los DALYs y un tercio de las muertes en el mundo debido a caídas fueron atribuibles a la baja DMO, y por lo tanto, prevenibles.