A recent study published in JAMA Network Open has revealed that secondhand smoke (SHS) exposure is linked to several negative effects on childhood myopia.
The study, conducted by Youjuan Zhang, Ph.D., and colleagues from The Chinese University of Hong Kong, utilized cross-sectional data from a population-based study involving 12,630 children aged 6 to 8 years. The findings indicate that SHS exposure is associated with greater myopic refraction, longer axial length, and increased odds of developing moderate and high myopia.
In the study, it was discovered that 32.4 percent of the children examined had been exposed to secondhand smoke (SHS). After adjusting for various factors such as age, sex, parental myopia, body mass index, near-work time, outdoor time, and family income, the researchers observed that SHS exposure was linked to greater myopic refraction (β = −0.09) and longer axial length (β = 0.05). Furthermore, children exposed to SHS had an increased likelihood of developing moderate and high myopia, with odds ratios of 1.30 and 2.64, respectively.
In younger children, the impact of secondhand smoke (SHS) exposure on spherical equivalence and axial length was heightened. For each additional year of SHS exposure in younger children, there was a 0.07-D decrease in spherical equivalence and a 0.05-mm increase in axial length. SHS exposure was also associated with an earlier average age of myopia onset (72.8 versus 74.6 months).
Moreover, a correlation was found between an increase in SHS exposure by 10 cigarettes per day and various negative effects. These effects included greater myopic refraction (β = −0.07), increased axial length (β = 0.04), and heightened odds of developing moderate and high myopia (odds ratios of 1.23 and 1.75, respectively). Additionally, an increase in SHS exposure was linked to an earlier onset of myopia (β = −1.30).
"Eliminating SHS exposure for eye care among children is important, particularly in families with young children," the authors concluded.
Youjuan Zhang et al, Analysis of Secondhand Smoke Exposure and Myopia Among Children Aged 6 to 8 Years in Hong Kong, JAMA Network Open (2023). DOI: 10.1001/jamanetworkopen.2023.13006
Ian G. Morgan, Exposure to Secondhand Smoke and Myopia in Children Aged 6 to 8 Years in Hong Kong, JAMA Network Open (2023). DOI: 10.1001/jamanetworkopen.2023.12995