title: Adult bone strength of children from single-parent families: the Midlife in the United States Study.
abstract: Bone health may be negatively impacted by childhood socio-environmental circumstances. We examined the independent associations of single-parent childhood and parental death or divorce in childhood with adult bone strength indices. Longer exposure to a single-parent household in childhood was associated with lower bone strength in adulthood.
  
  
  BACKGROUND
  Because peak bone mass is acquired during childhood, bone health may be negatively impacted by childhood socio-environmental disadvantage. The goal of this study was to determine whether being raised in a single-parent household is associated with lower bone strength in adulthood.
  
  
  METHODS
  Using dual-energy X-ray absorptiometry data from 708 participants (mean age 57 years) in the Midlife in the United States Biomarker Project, we examined the independent associations of composite indices of femoral neck bone strength relative to load (in three failure modes: compression, bending, and impact) in adulthood with the experience of single-parent childhood and parental death or divorce in childhood.
  
  
  RESULTS
  After adjustment for gender, race, menopause transition stage, age, and body mass index, each additional year of single-parent childhood was associated with 0.02 to 0.03 SD lower indices of adult femoral neck strength. In those with 9-16 years of single-parent childhood, the compression strength index was 0.41 SD lower, bending strength index was 0.31 SD lower, and impact strength index was 0.25 SD lower (all p values < 0.05). In contrast, parental death or divorce during childhood was not by itself independently associated with adult bone strength indices. The magnitudes of these associations were unaltered by additional adjustment for lifestyle factors and socioeconomic status in childhood and adulthood.
  
  
  CONCLUSIONS
  Independent of parental death or divorce, growing up in a single-parent household is associated with lower femoral neck bone strength in adulthood, and this association is not entirely explained by childhood or adult socioeconomic conditions or lifestyle choices.
authors.affiliation: Department of Medicine, David Geffen School of Medicine, Los Angeles, University of California, Los Angeles, UCLA Medicine/GIM, 911 Broxton Ave., 1st Floor, Los Angeles, CA, 90024, USA, ccrandall@mednet.ucla.edu.
authors.forename: C J
authors.initials: CJ
authors.lastname: Crandall
authors.forename: A S
authors.initials: AS
authors.lastname: Karlamangla
authors.forename: S S
authors.initials: SS
authors.lastname: Merkin
authors.forename: N
authors.initials: N
authors.lastname: Binkley
authors.forename: D
authors.initials: D
authors.lastname: Carr
authors.forename: G A
authors.initials: GA
authors.lastname: Greendale
authors.forename: T E
authors.initials: TE
authors.lastname: Seeman
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D015519:Bone Density / Q000502:physiology; D002648:Child; D004243:Divorce / Q000706:statistics & numerical data; D005260:Female; D005272:Femur Neck / Q000502:physiology*; D006801:Humans; D008016:Life Change Events; D008019:Life Style; D008297:Male; D008875:Middle Aged; D063129:Parental Death / Q000706:statistics & numerical data; D020954:Single-Parent Family; D012923:Social Class; D012931:Social Environment; D013314:Stress, Mechanical; D013997:Time Factors; D014481:United States