title: Abdominal obesity and hip fracture: results from the Nurses' Health Study and the Health Professionals Follow-up Study.
abstract: Abdominal obesity might increase fracture risk. We studied the prospective associations between waist circumference, waist-to-hip ratio, and hip fracture. The indicators of abdominal obesity were associated with increased hip fracture risk in women, but not in men. The increased risk was restricted to women with low physical activity.
  
  
  
  Low weight is an established risk factor for osteoporosis and hip fracture. However, the association between fat tissue, muscle, and bone is complex, and abdominal obesity might increase fracture risk. We studied the prospective associations between indicators of abdominal obesity and hip fracture in two large US cohorts.
  
  
  
  At baseline in 1986 and through biennial follow-up, information on hip fracture and potential risk factors was collected in 61,677 postmenopausal women and 35,488 men above age 50. Waist and hip circumferences were reported at baseline and updated twice.
  
  
  
  During follow-up, 1168 women and 483 men sustained a hip fracture. After controlling for known risk factors, there was a significant association in women between increasing waist circumference and hip fracture (RR per 10-cm increase 1.13 (95 % CI 1.04-1.23) and between increasing waist-to-hip ratio and hip fracture (RR per 0.1 unit increase 1.14 (95 % CI 1.04-1.23), but these associations were not seen in men. In women, both measures interacted with physical activity. Those in the highest (≥0.90) versus lowest (<0.75) category of waist-to-hip ratio had increased risk of hip fracture if their activity was less than the population median (RR = 1.61, 95 % CI 1.18-2.19) but not if their activity was higher (RR = 1.00, 95 % CI 0.72-1.40). A similar pattern was found for waist circumference.
  
  
  
  Indicators of abdominal obesity were associated with increased hip fracture risk after controlling for BMI in women. The increased risk was restricted to women with low physical activity. In men, no significant associations were found.
authors: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA. h.e.meyer@medisin.uio.no.|Section for Preventive Medicine and Epidemiology, Department of Community Medicine, University of Oslo, P.O. Box 1130 Blindern, 0318, Oslo, Norway. h.e.meyer@medisin.uio.no.|Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway. h.e.meyer@medisin.uio.no.
authors: H E
authors: HE
authors: Meyer
authors: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.|Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
authors: W C
authors: WC
authors: Willett
authors: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors: A J
authors: AJ
authors: Flint
authors: Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
authors: D
authors: D
authors: Feskanich
mesh_terms: D015992:Body Mass Index; D005260:Female; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D055105:Waist Circumference
keywords: Aging; Bone-fat interactions; Hip fracture; Obesity; Physical activity; Prospective