title: Vision in relation to lower extremity deficit in older women: cross-sectional and longitudinal study.
abstract: OBJECTIVE
  Vision problems are common experiences within the older population. This study aimed to examine the association between vision and lower extremity impairment.
  
  
  METHODS
  434 women aged 63-75 participated in visual acuity (VA) measurements at baseline and 313 persons at three-year follow-up. Measurements of lower extremity function included maximal isometric knee extension strength, leg extension power, maximal walking speed and standing balance.
  
  
  RESULTS
  At baseline, knee extension strength was lower among participants with visual impairment (VI) (273.2±6.4 N) compared to those with good vision (306.5±5.9 N, p<0.001) as well as leg extension power (95.2±2.7 W vs 104.2±2.6 W, p=0.009) and maximal walking speed (1.6±0.02 m/s vs 1.8±0.03 m/s, p<0.001). Higher velocity moment among persons with VI (53.5±2.7 mm²/s vs 42.7±1.4 mm²/s, p<0.001) indicated that persons with VI had poorer balance compared to persons with good vision. Decreased isometric knee extension strength (OR 1.26, 95% CI 1.09-1.45), poorer standing balance (OR 1.16, 95% CI 1.00-1.35) as well as lower maximal walking speed (OR 1.34, 95% CI 1.13-1.59) were associated with VI in the logistic regression models. Additionally, the association between poorer leg extension power and VI (OR 1.14, 95% CI 0.99-1.31) was of borderline statistical significance. In longitudinal analyses, VI did not predict decline in lower extremity function.
  
  
  CONCLUSIONS
  Lower extremity impairment was associated with VI among relatively healthy older women. However, change in lower extremity function was quite similar between the vision groups. It is possible that decreased VA may be a marker of underlying systemic factors or the aging process, which lead to poorer functional capacity, or there may be shared background factors, which lead to decreased vision and lower extremity impairment.
authors.affiliation: University of Jyväskylä, Department of Health Sciences, Gerontology Research Centre, Jyväskylä, Finland. jenni.kulmala@jyu.fi
authors.forename: Jenni
authors.initials: J
authors.lastname: Kulmala
authors.forename: Sarianna
authors.initials: S
authors.lastname: Sipilä
authors.forename: Kristina
authors.initials: K
authors.lastname: Tiainen
authors.forename: Olavi
authors.initials: O
authors.lastname: Pärssinen
authors.forename: Markku
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Taina
authors.initials: T
authors.lastname: Rantanen
mesh_terms: D000368:Aged; D000375:Aging; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000473:pathology; D007866:Leg / Q000502:physiology; D008137:Longitudinal Studies; D008875:Middle Aged; D053580:Muscle Strength; D004856:Postural Balance; D016059:Range of Motion, Articular; D012044:Regression Analysis; D014785:Vision, Ocular; D014792:Visual Acuity; D016138:Walking