Purpose
Studies of the relationship of smoking and macular degeneration(ARMD) have relied on self-reported smoking status. Cotinine, a nicotine metabolite, has been used to identify smoking deception and is considered to better represent exposure to nicotine from all sources including smokeless and environmental tobacco. This study looks at the association of serum cotinine(SC) to self-reported smoking status and ARMD in data from the National Health and Nutrition Examination Survey (NHANES).
Methods
Data from the 2005-2006 and 2007-2008 NHANES were used. Subjects over the age of 20 were asked if they currently smoked cigarettes every day, some days or never. During clinical assessment participants over the age of 12 were asked if they had used any products containing nicotine in the last five days. Ophthalmic photography (n=5575) was done for a subset of participants over the age of 40. ARMD was graded as absent, as mild (drusen >125 or pigment abnormalities) or severe (wet or geographic atrophy). SC level(n=6416) was sorted into a three level categorical variable of no measurable serum cotinine <0.5ng/ml, environmental exposure level ≥ .05ng/ml- <10ng/ml, and ≥ .10ng/ml active smoking. Associations between SC, self-reported nicotine use, and ARMD were evaluated using SAS Survey 9.3 accounting for the complex study design.
Results
Self-reported active cigarette smokers did not show increased odds of any level ARMD (OR 1.2 95% CI 0.8, 1.7). All source nicotine use in the last five days (OR 1.4 95%CI 1.04, 1.8) and SC at the active use level (OR 1.4 1.03, 1.9) were associated with ARMD in analyses controlling for age and ethnicity. SC at the environmental exposure level was not associated with ARMD (OR 0.9 95% CI 0.6, 1.8) Among those with any level of ARMD 8.5% (95% CI 3.1%, 13.5%) of persons who denied cigarette smoking had SC levels consistent with active nicotine use. Among those with ARMD who denied any nicotine use, 2.0%(95% CI 2.0 0.1 4.0) SC levels consistent with active nicotine use and 27.2%(95% CI 20.6, 33.8) had environmental level exposure.
Conclusions
Between 2-9% of persons with ARMD who deny nicotine use have SC levels consistent with active exposure. Current all form nicotine use and serum cotinine levels better reflected the increased odds of ARMD than did current cigarette smoking alone. This suggests nicotine exposure rather combustion products may be the source of increased ARMD risk.
Keywords: 412 age-related macular degeneration •
463 clinical (human) or epidemiologic studies: prevalence/incidence •
464 clinical (human) or epidemiologic studies: risk factor assessment