Risk factors for wet macular degeneration: a systematic review, with novel insights from the Scottish Heart Health Extended Cohort

BackgroundAge-related macular degeneration (AMD) is a major cause of vision loss worldwide. This study aimed to assess risk factors for wet AMD by two methods: assessing risk factors measured in the Scottish Heart Health Extended Cohort (SHHEC), and to systematically review the literature.MethodsEighteen thousand one hundred seven volunteers were recruited to SHHEC between 1984-1995, with risk factor data collected on recruitment. Hospital records were linked to study data up to 2017 and survival analysis was used to analyse risk factors and wet AMD. Literature published between 2000-2023 was searched for studies assessing risk factors for wet AMD, resulting in 5,503 papers. Following review, 7 studies were included in the systematic review.ResultsWithin the SHHEC data, 231 cases of wet AMD were reported. Increasing age (Hazard Ratio (HR) 10.51; 99% Confidence Interval (CI) 4.78-23.11) and smoking (HR 1.67; 99% CI 1.17-2.38) were significantly associated with an increased risk of wet AMD. Increased dietary intake of vitamin K (HR 0.56; 99% CI 0.34-0.94) was associated with a decreased risk of wet AMD.According to a systematic review, smoking, high Body mass index, heavy alcohol intake, increased systolic blood pressure, increased pulse pressure, and high levels of C-reactive protein and serum triglycerides in the blood may be associated with an increased risk of wet AMD. However, the studies provide mixed evidence and no conclusive results.ResultsWithin the SHHEC data, 231 cases of wet AMD were reported. Increasing age (Hazard Ratio (HR) 10.51; 99% Confidence Interval (CI) 4.78-23.11) and smoking (HR 1.67; 99% CI 1.17-2.38) were significantly associated with an increased risk of wet AMD. Increased dietary intake of vitamin K (HR 0.56; 99% CI 0.34-0.94) was associated with a decreased risk of wet AMD.According to a systematic review, smoking, high Body mass index, heavy alcohol intake, increased systolic blood pressure, increased pulse pressure, and high levels of C-reactive protein and serum triglycerides in the blood may be associated with an increased risk of wet AMD. However, the studies provide mixed evidence and no conclusive results.ConclusionWe have demonstrated that increasing age and smoking are high-risk factors for the development of wet AMD, while vitamin K is associated with a reduced risk of wet AMD.