{
  "abstract": "Backgrounds/aims Any association of secondhand smoke (SHS) with refractive astigmatism (RA) and corneal astigmatism (CA) remains unknown. This study aims to investigate the associations of SHS exposure with RA and CA in schoolchildren.Methods We conducted a population-based, cross-sectional study involving 11 545 children aged 6–8 years from the Hong Kong Children Eye Study. SHS exposure was evaluated through questionnaires, quantified by parental smoking. Child astigmatism was defined by cycloplegic autorefraction and keratometry. The associations of SHS exposure with risks and magnitudes of RA and CA were tested using logistic and linear regressions.Results 26.47% of children were exposed to SHS (mean age±SD, 7.35±0.88 years; 51.1% boys). SHS exposure was associated with the risk (OR (95% CI), 1.11 (1.00 to 1.23), p=0.04) and magnitude of RA (β (SE), −0.03D (0.01), p=0.046). Exposure to ≥10 cigarettes/day was associated with risk (OR (95% CI), 1.64 (1.23 to 2.17), p<0.001) and magnitude of RA (β (SE), −0.11D (0.05), p=0.01). Exposure to ≥20 cigarettes/day was associated with RA risk (OR (95% CI), 2.18 (1.48 to 3.19), p<0.001), RA magnitude (β (SE), −0.20D (0.06), p=0.001) and CA magnitude (β (SE), 0.17D (0.070, p=0.01). Test for linear trend with SHS quantity was significant for both risk (p=0.004) and magnitude of RA (p=0.03).Conclusion SHS exposure increases the risk and severity of child RA dose-dependently. Reduction of smoking in the presence of children or better provision of a smoke-free living environment for children is recommended.",
  "authors": [
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Erica Shing"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong",
        "Department of Ophthalmology and Visual Sciences, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, Hong Kong"
      ],
      "name": "Ka Wai Kam"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Yuzhou Zhang"
    },
    {
      "affiliations": [
        "Department of Ophthalmology, The University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Xiu Juan Zhang"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong",
        "Department of Ophthalmology and Visual Sciences, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, Hong Kong"
      ],
      "name": "Arnold Shau Hei Chee"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Mandy P H Ng"
    },
    {
      "affiliations": [
        "Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Patrick Ip"
    },
    {
      "affiliations": [
        "Tianjin Eye Hospital, Tianjin, Tianjin, China"
      ],
      "name": "Wei Zhang"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong",
        "Department of Ophthalmology and Visual Sciences, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, Hong Kong"
      ],
      "name": "Alvin L Young"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong",
        "Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Hong Kong Eye Hospital, Hong Kong, Hong Kong",
        "Department of Ophthalmology, Hong Kong Children’s Hospital, Hong Kong, Hong Kong"
      ],
      "name": "Clement C Tham"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Chi Pui Pang"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong",
        "Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, Hong Kong"
      ],
      "name": "Li Jia Chen"
    },
    {
      "affiliations": [
        "Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Department of Ophthalmology & Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong",
        "Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, Hong Kong",
        "Hong Kong Eye Hospital, Hong Kong, Hong Kong",
        "Department of Ophthalmology, Hong Kong Children’s Hospital, Hong Kong, Hong Kong"
      ],
      "name": "Jason C Yam"
    }
  ],
  "title": "Association of secondhand smoke exposure with child astigmatism in the Hong Kong children eye study",
  "uid": "7e75b263-afe4-5089-89a3-e5f87686fb51"
}