title: Increased risk of hip fracture among spouses-evidence of a homogamy effect.
abstract: Spouses tend to share habits and therefore have an increased risk of same diseases. We followed all married couples in Sweden, born 1902 to 1942, in hospital records from 1987 to 2002, and found that individuals whose spouse had a hip fracture had an increased risk of hip fracture.
  
  
  
  The purpose of this study was to determine whether spouses of hip fracture patients have an elevated risk of hip fracture.
  
  
  
  We performed a retrospective cohort study of all couples married for at least 5 years in Sweden and born between 1902 and 1942 (n = 904,451) and all patients registered with a hip fracture (n = 218,285) in the National Inpatients Register in Sweden from 1987 to 2002.
  
  
  
  During the period 1987 to 2002 hip fractures occurred among spouses in 4212 married couples. The hazard ratio (HR) for hip fracture in a married woman following hip fracture in the husband was 1.11 (95 % confidence interval 1.07 to 1.16) compared to a woman whose husband did not have hip fracture. The corresponding HR for a married man was 1.20 (1.15 to 1.26) compared to a man whose wife did not have hip fracture. The risk was significantly elevated over the age range 60 to 90 years. The increased risk for hip fracture among spouses remained after adjustments for income, education, geographical latitude and urbanisation. In a common model with spouses and their siblings, the HR for spousal effect were 1.63 (1.01 to 2.64) and for sibling effect 2.18 (1.55 to 3.06) compared to married with spouse and sibling respectively without hip fracture.
  
  
  
  The novel finding of an increased risk for hip fracture among spouses provides evidence indicating that there is a homogamy effect due to common social and lifestyle factors but could also be due to assortative mating.
authors: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 431 80, Mölndal, Sweden.
authors: C H
authors: CH
authors: Vala
authors: Department of Biostatics, Chalmers University, 412 58, Gothenburg, Sweden.
authors: A
authors: A
authors: Odén
authors: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 431 80, Mölndal, Sweden.|Centre for Bone and Arthritis Research (CBAR), Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden.
authors: M
authors: M
authors: Lorentzon
authors: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 431 80, Mölndal, Sweden.
authors: V
authors: V
authors: Sundh
authors: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 431 80, Mölndal, Sweden.
authors: H
authors: H
authors: Johansson
authors: Department of Orthopedics and Clinical Sciences, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden.
authors: M
authors: M
authors: Karlsson
authors: Department of Orthopedics and Clinical Sciences, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden.
authors: B
authors: B
authors: Rosengren
authors: Centre for Bone and Arthritis Research (CBAR), Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden.
authors: C
authors: C
authors: Ohlsson
authors: Department of Psychology, University of Gothenburg, 405 30, Gothenburg, Sweden.
authors: B
authors: B
authors: Johansson
authors: Centre for Metabolic Bone Disease, Medical School, University of Sheffield, Sheffield, S10 2RX, UK.
authors: J
authors: J
authors: Kanis
authors: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, 431 80, Mölndal, Sweden. dan.mellstrom@vgregion.se.|Centre for Bone and Arthritis Research (CBAR), Sahlgrenska Academy, University of Gothenburg, 413 45, Gothenburg, Sweden. dan.mellstrom@vgregion.se.
authors: D
authors: D
authors: Mellström
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005192:Family Health / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D058866:Osteoporotic Fractures / Q000453:epidemiology* / Q000209:etiology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D018454:Spouses / Q000706:statistics & numerical data*; D013548:Sweden / Q000453:epidemiology
keywords: Assortative mating; Hip fracture; Homogamy; Osteoporosis