Influence of Obesity on Vertebral Fracture Prevalence and Vitamin D Status in Postmenopausal Women

A. El Maghraoui; S. Sadni; A. El Maataoui; A. Majjad; A. Rezqi; Z. Ouzzif; A. Mounach

Disclosures

Nutr Metab. 2015;12(44) 

In This Article

Results

Patient Demographics

In this series of 429 women, the mean ± SD (range) age, weight and BMI were 59.5 ± 8.3 (50 to 83) years, 75.8 ± 13.3 (35 to 165) kgs and 29.9 ± 5.2 (14.6 to 50.8) kg/m2, respectively (Table 1). Prevalence of obesity (BMI > 30) was 45.6 % in our population. According to the WHO classification, 90 had osteoporosis (21.0 %) and 252 had osteopenia (58.7 %). None of the women were current smokers while 57 (13.3 %) women reported a history of peripheral fracture after the age of 50. The mean (SD) 25 (OH) D level in this series was 14.5 ng/ml (12.4). Prevalence of hypovitaminosis D was 78.1 % (335/429) for levels < 20 ng/ml and 90.39 (390/429) for levels < 30 ng/ml. Two hundred and twenty four women (52.2 %) had vitamin D deficiency (<10 ng/ml).

Vertebral Visualization and Fracture Identification on VFA

In these 429 women, 62.7 % of vertebrae from T4–L4 and 99 % from T8–L4 were adequately visualized on VFA. The percentage of vertebrae not visualized at T4, T5, and T6 levels was 57.1 %, 35.2 %, and 20.1 % respectively.

VFs were identified in 248 (57.8 %): 172 (40.1 %) had grade 1 and 76 (17.7 %) had grade 2 or 3. Fractures were most common in the mid-thoracic spine and at the thoracolumbar junction.

Comparison between women according to their BMI showed that obese women had a higher lumbar spine and total hip BMD and less proportion of women with osteoporosis and VFs grade 2/3 than lean and overweight women (Table 2).

The group of women with moderate/severe VFs had a statistically significant higher age, number of parity, years since menopause and lower weight, height, and lumbar spine and total hip BMD and T-scores than those without a VFA-identified vertebral fracture (Table 3). They also have lower levels of 25 (OH) D and higher proportion of women with vitamin D below 20 ng/ml.

In this study, VFA-identified fractures occurred in 145 (57.1 %) women with osteopenia (44 (17.5 %) had grade 2/3) and in 65 (71.9 %) women with osteoporosis (23 (25.6 %) had grade 2/3) (p < 0.0001). Interestingly, a fracture was identified on VFA in 38 (43.6 %) of women with normal BMD (9 (10.3 %) had grade 2/3 VFs).

Among obese women (n = 210 (49.1 %)), VFs prevalence was higher in those with osteoporosis (23.1 %) vs. those with osteopenia (12.0 %) and normal BMD (4.5 %) (p < 0.0001). The prevalence of hypovitaminosis D was also higher even though the difference was not significant (100 %, 90.0 % and 54.5 % respectively; p = 0.34)

Risk Factors

The prevalence of VFA-detected fractures globally increased significantly for both grade 1 and grade 2/3 VFs with age (p < 0.0001) and as BMD (p < 0.0001) and BMI declined (p < 0.0001).

Stepwise regression analysis showed that presence of osteoporosis was independently related to BMI and history of fractures (Table 4) while the presence of VFs grade 2/3 was independently related to age, hypovitaminosis D and years of menopause (Table 5).

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