title: Anticholinergic medication use and falls in postmenopausal women: findings from the women's health initiative cohort study.
abstract: BACKGROUND
  Results from studies assessing the association between anticholinergic use and falls are mixed, and prior studies are limited in their ability to control for important potential confounders. Thus, we sought to examine the association between anticholinergic medication use, including over-the-counter medications, and recurrent falls in community-dwelling older women.
  
  
  METHODS
  We analyzed data from a prospective cohort study of women aged 65 to 79 years from the Women's Health Initiative Observational Study and Clinical Trials. Women were recruited between 1993 and 1998, and analyses included 61,451 women with complete information. Medications with moderate or strong anticholinergic effects were ascertained directly from drug containers during face-to-face interviews. The main outcome measure was recurrent falls (≥2 falls in previous year), which was determined from self-report within 1.5 years subsequent to the medication assessment.
  
  
  RESULTS
  At baseline, 11.3 % were using an anticholinergic medication, of which antihistamines (commonly available over-the-counter) were the most common medication class (received by 45.2 % of individuals on anticholinergic medication). Using multivariable GEE models and controlling for potential confounders, the adjusted odds ratio for anticholinergic medication use was 1.51 (95 % CI, 1.43-1.60) for recurrent falls. Participants using multiple anticholinergic medications had a 100 % increase in likelihood of recurrent falls (adjusted odds ratio 2.00, 95 % CI 1.73-2.32). Results were robust to sensitivity analysis.
  
  
  CONCLUSIONS
  Anticholinergic medication use was associated with increased risk for recurrent falls. Our findings reinforce judicious use of anticholinergic medications in older women. Public health efforts should emphasize educating older women regarding the risk of using over-the-counter anticholinergics, such as first-generation antihistamines.
authors.affiliation: School of Pharmacy, University of Washington, 1959 NE Pacific St, H375G, Box 357630, Seattle, WA, 98195-7630, USA. zmarcum@uw.edu.
authors.forename: Zachary A
authors.initials: ZA
authors.lastname: Marcum
authors.affiliation: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors.forename: Heidi S
authors.initials: HS
authors.lastname: Wirtz
authors.affiliation: WHI Clinical Coordinating Center, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA, 98109, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Pettinger
authors.affiliation: Division of Epidemiology, UC San Diego, 9500 Gilman Dr #0725, La Jolla, CA, 92093, USA.
authors.forename: Andrea Z
authors.initials: AZ
authors.lastname: LaCroix
authors.affiliation: College of Public Health, Department of Epidemiology, University of Iowa, 145 N Riverside Dr, 100 CPHB, Iowa City, IA, 52242, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Carnahan
authors.affiliation: Department of Epidemiology, University of Pittsburgh, A510 Crabtree Hall, Pittsburgh, PA, 15261, USA.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.affiliation: Departments of Medicine and Nutritional Sciences, University of Arizona Cancer Center, 1515 N Campbell Ave, PO Box 245024, Tucson, AZ, 85724, USA.
authors.forename: Jennifer W
authors.initials: JW
authors.lastname: Bea
authors.affiliation: School of Pharmacy, University of Washington, 1959 NE Pacific St, H375G, Box 357630, Seattle, WA, 98195-7630, USA.
authors.forename: Shelly L
authors.initials: SL
authors.lastname: Gray
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D018680:Cholinergic Antagonists / Q000008:administration & dosage / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006633:Histamine Antagonists / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D017698:Postmenopause; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D014481:United States
chemical_list: D018680:Cholinergic Antagonists; D006633:Histamine Antagonists
keywords: Anticholinergic; Community dwelling; Falls; Older adults