Diabetes mellitus and tobacco chewing may alter corneal endothelial hexagonality and reduce endothelial cell counts, according to research published in Eye. These findings may warrant thorough corneal evaluations for patients with diabetes who use chewing tobacco prior to undergoing intraocular surgery, the report suggests.
Researchers included 948 participants who chewed tobacco (with diabetes mellitus, n=473) and 286 age- and sex-matched control group participants who did not chew tobacco (with diabetes mellitus, n=139) in the investigation. The study participants underwent non contact specular microscopy to measure corneal endothelial parameters including endothelial cell count, coefficient of variation, hexagonality, and central corneal thickness and the team examined associations between these variables and diabetes mellitus and chewing tobacco.
Endothelial cell counts and hexagonality were significantly reduced among participants who chewed tobacco compared with those who did not (2369.6 vs 2421.7 cells/mm2; P =.024 and 42.1% vs 43.1%; P =.009, respectively). Diabetes status similarly affected both parameters, demonstrated by lower endothelial cell counts and hexagonality among individuals with diabetes who chewed tobacco (P ≤.005 for both). The investigation did not determine any associations between diabetes mellitus or chewing tobacco and central corneal thickness or coefficient of variation values.
Male sex, hemoglobin A1C (HbA1C) levels of 7.5% or less, and a diabetes mellitus duration of 20 years or less correlated with decreased endothelial cell counts in individuals who chewed tobacco (P =.025; P =.014; and P =.007, respectively), while age older than 50 years, female sex, HbA1C levels of 7.5% or less, and diabetes mellitus of more than 20 years correlated with reduced hexagonality (P =.034; P =.032; P =.037; and P =.016, respectively).
“[C]hewing tobacco has a propensity to negatively affect the corneal health, especially in an already compromised state like diabetes,” the researchers explain. “With a higher chance of having an intraocular manipulation like cataract surgery in ageing corneas, these potential prognostic factors demand a high level of suspicion and therefore a thorough corneal evaluation before any surgery is planned.”
Study limitations include ethnic homogeneity among the cohort, which may limit the globalization of these findings.
Jha A, Verma A, Priya C. Effects of chewing tobacco on corneal endothelium in patients with diabetes mellitus. Eye (Lond). Published online April 18, 2023. doi:10.1038/s41433-023-02515-x