Aim To assess whether cardiorespiratory fitness (CRF) and handgrip strength, two objective markers of physical fitness, are associated with age-related macular degeneration (AMD).
Methods We analysed cross-sectional data from the population-based Study of Health in Pomerania (2008–2012) including 1173 adult men and women aged 20–79 years. Fundus photography of the central retina was recorded with a non-mydriatic camera, and images were graded according to an established clinical AMD classification scale by an experienced reader. CRF was measured using peak oxygen uptake (peakVO2), oxygen uptake at the anaerobic threshold (VO2@AT), and maximum power output (Wmax) from standardised cardiopulmonary exercise testing on a bicycle ergometer according to a modified Jones protocol. Handgrip strength was assessed using a handheld dynamometer. Adjusted prevalence ratios (PR) for the associations of peakVO2, VO2@AT, Wmax and handgrip strength with AMD were derived from multivariable Poisson regression models.
Results PeakVO2, VO2@AT, Wmax and handgrip strength were not associated with AMD. Adjusted PR for AMD associated with a 1-SD increment in peakVO2, VO2@AT, Wmax and handgrip strength were 1.05 (95% CI 0.82 to 1.34), 0.96 (95% CI 0.78 to 1.18), 1.10 (95% CI 0.86 to 1.41) and 1.01 (95% CI 0.79 to 1.30), respectively. These associations were not modified by age, sex, smoking, body mass index and diabetes. Estimates in sensitivity analysis for confounding, selection bias and missing data were similar.
Conclusion In our study, CRF and handgrip strength were not associated with AMD. Nevertheless, longitudinal studies with bigger sample sizes are needed to furtherly examine these associations.
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Contributors AK, CJ, CM and SEB drafted the manuscript. CJ and LL were involved in data collection and AMD grading. SEB, AK and TI analysed the data. MB, TI, SG, MD, RE, KV, SBF, FT, LL and HV critical revised the manuscript for important intellectual content. All authors provided administrative, technical or material support.
Funding The Study of Health in Pomerania is part of the Community Medicine Research Network of the University Medicine Greifswald, which was funded by the German Federal Ministry for Education and Research (BMBF, Grants 01ZZ0403, 01ZZ0103, 01GI0883), the Ministry for Education, Research and Cultural Affairs, as well as the Ministry for Social Affairs of the State Mecklenburg-West Pomerania.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.
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