Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Epidemiology and Biostatistics

Supervisor

Karp, Igor

Abstract

Background: Cataracts are the leading cause of blindness globally, so advancing the understanding their etiology is of paramount importance for development of the preventive interventions. The findings for the association of alcohol intake and fruit and vegetable consumption with cataracts in previous literature were inconsistent.

Objective: The first study objective was to assess whether alcohol intake increases the risk of cataracts among adults. The second study objective was to assess whether fruit and vegetable consumption reduces the risk of cataracts among adults.

Methods: A retrospective cohort study design was used. Data were obtained from the Household, Longitudinal component of the Canadian National Population Health Survey (NPHS) (1994-2011) cohort among adults aged 40 years or older. The first study objective used data from cycle 1 (1994/1995) through cycle 9 (2010/2011). Data for the second objective were obtained from the last five cycles of this survey (2002/2003-2010/2011). Alcohol use was measured as drinks per month. Fruit and vegetable consumption was assessed as daily servings. The subjects were followed until the occurrence of a cataract, death, end of the NPHS survey (2010/2011), or loss to follow-up, whichever came first. The research questions were addressed by fitting the Cox proportional hazards regression models with the inclusion of time-varying explanatory variables.

Results: The first study included 9,889 respondents, with 1,978 incident cataracts and an incidence rate of 19.2 per 1,000 person-years for the study population from cycle 1 to cycle 9 in NPHS. A total of 7,388 respondents who met our inclusion and exclusion criteria were identified through cycle 5 to cycle 9 for the second study, of which 1,019 developed cataracts over the follow-up period, the incidence rate was 19.7 per 1,000 person-years. After adjusting for potential confounders, the hazard ratios for alcohol intake and fruit and vegetable consumption were 1.00 (95% confidence interval [CI]: 0.95 to 1.04) and 1.04 (95% CI: 0.91 to 1.19), respectively.

Conclusion: The results suggest that alcohol use and fruit and vegetable consumption are not statistically significantly associated with the risk of cataracts.

Summary for Lay Audience

The incidence of cataracts has grown significantly and become the leading cause of blindness globally. A cataract is a chronic condition, and many factors have been identified as being related to this condition. Risk factors such as age and sex are examples of non-modifiable factors thought to be related to developing cataracts. We assessed the association of two dietary factors (namely, alcohol use and fruit and vegetable intake) with cataracts. We used National Population Health Survey (NPHS) to examine the impact of these dietary factors on cataracts among adults. Our first study used data from NPHS to investigate whether alcohol use increases the risk of cataracts. We found that alcohol use was not statistically significantly associated with the risk of developing cataracts among adults. Our second study examined the association of fruit and vegetable intake with cataracts. We found no statistically significant association between fruit and vegetable intake and the development of cataracts.

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