• Impact of Secondhand Smoke on the Choroid of Children

    Written By: Lynda Seminara
    Selected and Reviewed By: Neil M. Bressler, MD, and Deputy Editors

    Journal Highlights

    JAMA Ophthalmology, December 2019

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    Yuan et al. assessed the relationship between choroidal thickness and sec­ondhand smoke exposure in children between the ages of 6 and 8. They found that secondhand smoke correlates with choroidal thinning in an exposure-dependent manner.

    For this study, the researchers included 1,400 patients recruited from the population-based Hong Kong Children Eye Study. All participants underwent detailed ophthalmic investigations, including measurement of choroidal thickness via swept-source optical coherence tomography. History of secondhand cigarette smoke was ob­tained from a questionnaire completed by parents or guardians. The correla­tion between choroidal thickness and exposure to secondhand smoke was assessed with multiple linear regression analyses, controlling for confounding factors.

    Of the 1,400 participating children, 459 (32.8%) had been exposed to secondhand cigarette smoke. After ad­justment for age, sex, body mass index, axial length, and birth weight, second­hand smoke was found to correlate with thinner choroidal parameters. When choroidal measurements were compared, those of smoke-exposed children were 8.3 μm thinner in the central subfield, 7.2 μm narrower in the inner inferior, 6.4 μm narrower in the outer inferior, 6.4 μm thinner in the inner temporal, and 7.3 μm thinner in the outer temporal.

    Choroidal thinning was more com­mon in families with multiple smokers and in homes with larger amounts of secondhand smoke. For each additional smoker, choroidal thinning increased by 7.86 μm in the central subfield, 4.51 μm in the outer superior, 6.23 μm in the inner inferior, 5.59 μm in the outer inferior, 6.06 μm in the inner nasal region, and 6.55 μm in the outer nasal region. Increasing exposure to second­hand smoke by one cigarette per day was linked to further choroidal thinning of 0.54 μm in the central subfield, 0.42 μm in the inner temporal sector, and 0.47 μm in the outer temporal sector.

    Although these findings suggest that secondhand smoke is linked to choroi­dal thinning in children, the authors cautioned that the association does not necessarily indicate a causal effect. (Also see related commentary by Cécile Delacourt, PhD, in the same issue.)

    The original article can be found here.