Near Visual Impairment Incidence in Relation to Diabetes in Older People: The Three-Cities Study

Abstract

Objectives: To characterize the relationship between diabetes mellitus (DM) and future risk of near vision impairment (VI) in a community-dwelling population of older people.

Design: Seven-year population-based longitudinal study.

Setting: Three-Cities Study, a French prospective study designed to assess the risk of cognitive and functional decline attributable to vascular factors.

Participants: Community-dwelling individuals aged 65 and older (N = 8,412).

Measurements: DM was determined at baseline according to self-reported DM, antidiabetic treatment, and fasting blood glucose. Near visual acuity was measured at baseline and 2, 4, and 7 years later. Near VI was defined as a Snellen score greater than 20/30.

Results: DM was associated with a higher risk of near VI in an adjusted model (hazard ratio (HR) = 1.24, 95% confidence interval (CI) = 1.02-1.52, P = .03). Because of an interaction between Body Mass Index (BMI) and diagnosed DM, the longitudinal analyses were stratified according to BMI category. DM was associated with greater risk of near VI only in underweight (BMI <21.0 kg/m² , HR = 2.89, 95% CI = 1.18-7.03) and normal-weight (BMI 21.0-24.9 kg/m² , HR = 1.60, 95% CI = 1.10-2.32), but not overweight (P = .69) and obese (P = .09) subjects.

Conclusion: DM is a risk factor for near VI in older people, particularly in those with a low or normal BMI. This risk profile should be taken into account in older adults to support their independence.

Keywords: body mass index; diabetes mellitus; incidence; near vision impairment.