Vascular risk factors and rhegmatogenous retinal detachment: a follow-up of a national cohort of Swedish men

Background We aimed to investigate the role of vascular risk factors in the genesis of rhegmatogenous retinal detachment (RRD) using data from a large cohort of Swedish conscripts. Methods We used data from a nationwide cohort of 49 321 Swedish men born during 1949-1951, conscripted for compulsory military service in 19691970 with nearly complete follow-up to 2009. Information on surgically treated RRD between 1973 and 2009 was collected from the National Patient Register. We fitted Cox regression models stratified on myopia degree and including blood pressure levels, body mass index and cigarette smoking. Population attributable fractions of RRD were estimated through maximum likelihood methods. Results We observed 262 cases of RRD in 1 725 770 person-years. At multivariate analysis, the number of cigarettes per day showed a reverse association with the risk of RRD (p for trend 0.01). Conscripts with obesity presented a higher risk compared with normal subjects (adjusted HR 2.51, 95% CI 1.02 to 6.13). We found weak evidence of an association between blood pressure and RRD (HR for men with hypertension compared with normotension 1.41, 95% CI 0.93 to 2.13). All the observed associations were stronger when the analysis was restricted to non-myopic conscripts. In particular, the HR for hypertension was 2.33 (95% CI 1.30 to 4.19) compared with normotension. If this association is causal, we estimated that 42.0% of RRD cases (95% CI 11.5% to 62.0%) occurring among non-myopics are attributable to elevated blood pressure. Conclusions Vascular risk factors may be important determinants of RRD, particularly among non-myopics. Further investigations on the role of hypertension and obesity are needed.