Skin Intrinsic Fluorescence and Selected Measures of Visual Function and aging in Older Adults

Purpose: Functional, structural and metabolic decline in many systems and in combination contribute to biologic aging and may be manifest as increased risk of morbid events such as neuropathy, albuminuria, and coronary artery disease or mortality. A biologic marker of aging may be a useful tool in identifying persons at increased risk of morbidity or mortality. We have measured skin intrinsic fluorescence (SIF) in a group of older adults to determine whether this easily determined measure could serve as such a biomarker. Methods: Survivors of a population based study of older adults in a moderate sized Midwestern town. Of the 1181 persons participating, 939 had measures of skin intrinsic fluorescence (SIF) and at least one functional or diagnostic characteristic at the most recent examination. Characteristics such as blood pressure, forced expiratory volume, vision, time to walk a standard course and medical history and their associations with SIF measures were examined. Mortality after the last examination with respect to SIF was also investigated. There were 118 deaths among those who participated in this phase of the study. All analyses pertinent to these findings were adjusted for age. Results: SIF measures were significantly associated with low contrast sensitivity, more errors on frequency doubling technology testing (loss of peripheral vision), self-reported poor vision, slow gait, poor forced expiratory volume, and self-reported poor health. SIF was also associated with increased risk of death. All of these analyses were adjusted for age. Conclusions: Skin intrinsic fluorescence provides easily obtained markers of age-related functional outcomes, suggesting SIF measurements may be useful to identify persons who may benefit from more frequent medical scrutiny to decrease morbidity and mortality.