5.4 Risk and Protective Factors for Retinal Vein Occlusion

5.3.3 Central Retinal Vein Occlusion

In the BDES, the 5-year and 15-year incidences of CRVO were 0.2% and 0.5%, respectively.29 In the BMES, the 10-year incidence of CRVO was 0.4%.9

5.4Risk and Protective Factors for Retinal Vein Occlusion

The epidemiologic factors that have been associated with BRVO include age, male gender, and higher body mass index.7 The EDCCS found no epidemiologic risk factors for CRVO.52 In univariate and multivariate models, the following epidemiologic factors were protective against CRVO: alcohol consumption, more education, and increased daily physical activity.52

5.4.1 Age

Because RVOs have multiple factors that contribute to pathogenesis, and many of them are influenced by age (e.g., arteriolar sclerosis, hypertension, malignancy, and estrogen replacement therapy), an association between aging and RVO is not only plausible but also has been found repeatedly in studies. This association holds for pooled RVO, BRVO, and

CRVO.29,33,37,44

There are no epidemiological studies of RVO in younger people (age 40 or less). Such estimates of epidemiological variables as can be made derive from methodologically flawed study designs such as clinic-based case series and retrospective mining of insurance databases.39

5.4.1.1 Pooled Retinal Vein Occlusion

In the BDES, among a population of age 43–86, the mean age for subjects with pooled RVO was 70.1 (95% CI 67.0–73.3) compared to 61.8 (95% CI 61.4–62.1) for subjects without RVO.8 In the

BMES, among a population of age 49 and above, the mean age for subjects with pooled RVO was 71.6 (95% CI 69.2–74.0) compared to 65.9 (95% CI 65.6–66.3) for subjects without RVO.8 Younger patients make up a minority of cases of pooled RVOs. In case series, the proportion of patients with RVO of age less than 45 ranges from 5% to 12%.39

Increasing age is significant risk factor for prevalence of pooled RVO (Fig. 5.1).46 Its influence is so strong that other factors are typically examined after adjusting for its effect.39

Age is also associated with incidence of pooled RVO.10 The incidence of pooled RVO in persons 70–79 is threefold higher than that in persons age 50–59.39

5.4.1.2 Branch Retinal Vein Occlusion

In five pooled retrospective series of 877 cases of BRVO, the weighted mean age of onset was 66 ± 11 years.2,11,12,25,55 In a consecutive case series of 348 patients with BRVO from a single clinic, 5% of patients were less than 45, 44% were 45–64, and 52% were greater than or equal to 65.20 The median age was 66 with range 20–93.20 In a case series of 3,490 patients with BRVO, BRVO in patients less than or equal to 49 years constituted only 2%.36 BRVO has been reported in patients as young as 17.36

Prospective, population-based studies confirm the suggestions of retrospective series (Figs. 5.2 and 5.3).39 In the BDES, increasing age was a significant risk factor for prevalence (P < 0.0001) and for 5-year incidence of BRVO (P < 0.001).29 In the BDES, persons greater than or equal to 75 years were 6.7 times (95% CI 2.2, 20.4) as likely to have BRVO as persons 43–54 years of age.29 In the BDES, a multivariate analysis showed that increasing age was associated independently with 15-year incidence of BRVO. Each decade of increasing age was associated with an OR 1.71 (95% CI 1.32–2.20, P < 0.001).33 In both the EDCCS and the BMES, increasing age was a risk factor for BRVO.9,51 The 10-year incidences of BRVO in the less than 60-year-old, 60to 69-year-old, and greater than or equal to 70-year- old age groups were 0.9%, 1.4%, and 1.9%, respectively.9

Fig. 5.1 Prevalence of pooled RVO versus age from three population-based studies. BES Beijing Eye Study, BMES Blue Mountains Eye Study, BDES Beaver Dam Eye Study

Prevalence of pooled RVO versus age

Fig. 5.2 Prevalence of BRVO by age based on 15 pooled population-based studies (Data from Rogers et al.44)

Prevalence of BRVO versus age

5.4.1.3 Central Retinal Vein Occlusion

Although more common as age increases, CRVO can occur in patients as young as 4 years.1 In five pooled retrospective series of 740 cases of CRVO, the weighted mean age of onset was 65±14 years.2,11,12,19,35 In a case series of 612 patients

with CRVO from a single clinic, 16% of patients were less than 45, 35% were 45–64, and 49% were greater than or equal to 65.20 The median age was 64.5 with range 16–100.20 In another series, percent of patients with CRVO were older than 50.15

Population-based studies confirm these suggestions. In the BDES, increasing age was a sug-

Fig. 5.3 Five-year incidence of BRVO versus age in the BDES Beaver Dam Eye Study (Data from Klein et al.29)

Five−year incidence of BRVO versus age

Fig. 5.4 Prevalence of CRVO by age based on 15 pooled population-based studies (Data from Rogers et al.44)

Prevalence of CRVO versus age

gestive risk factor for prevalence (P = 0.06) and for 5-year incidence of CRVO (P = 0.10) (Figs. 5.4 and 5.5).29 A multivariate analysis of the 15-year incidence of CRVO showed that age was an independent risk factor. Each decade’s increase in age was associated with an OR of 1.58 (95% CI 1.00–2.49, P = 0.05) for development of CRVO.37

In the BMES, 87% of patients with CRVO at baseline were 70 years of age or older and no incident CRVO occurred in the group younger than 60.9,39 Increasing age was a risk factor for incidence of CRVO.9 The 10-year incidences of CRVO in the 60to 69-year-old and 70-year-old or older age groups were 0.4% and 1.1%, respectively.9