前沿资讯丨二手烟或导致视力下降

二手烟是成年人眼睛健康的一大威胁。许多研究表明，吸烟会增加患眼部疾病的风险，这些疾病会影响人们以后的生活，比如白内障和年龄相关性黄斑变性(AMD)，这是导致失明的主要原因。但是，二手烟会对儿童的视力造成威胁吗?一项来自香港的新研究表明二手烟会造成儿童视力下降。研究人员发现，长期处于二手烟环境下的6岁儿童就已经出现了眼部损伤的迹象。

眼睛最容易被香烟烟雾伤害的部位之一叫做脉络膜。脉络膜是位于眼睛后部的一个密集的血管网。眼后段不同位置的脉络膜，其厚度不同。正常人黄斑中心凹脉络膜厚度为272~448 μm。距中心凹6 mm范围，上方最厚，中心凹次之，然后是颞侧和下方，鼻侧最薄。

它主要负责为视网膜提供氧气和营养，保证成像清晰。研究表明，吸烟者和吸二手烟的人脉络膜较薄。脉络膜变薄与威胁视力的年龄相关性黄斑变性的发展有关。

参考文献：

Association of Secondhand Smoking Exposure With Choroidal Thinning in Children Aged 6 to 8 Years

The Hong Kong Children Eye Study

Nan Yuan, MPhil1; Jian Li, PhD1,2; Shumin Tang, PhD1,3; et al

Objective

To assess the association between choroidal thickness and secondhand smoking exposure in children.

目的

探讨儿童脉络膜厚度与二手烟的关系。

Design, Setting, and Participants

Children aged 6 to 8 years were consecutively recruited from January 2016 to July 2017 from the population-based Hong Kong Children Eye Study at the Chinese University of Hong Kong Eye Centre. All participants underwent detailed ophthalmic investigations. Choroidal thickness was measured by swept-source optical coherence tomography, with built-in software that automatically segmented the choroid layer to analyze its terrain imagery. History of secondhand smoking was obtained from a questionnaire. Multiple linear regression analyses were performed to assess the correlation between choroidal thickness and secondhand exposure when controlling for confounding factors. Analysis began July 2018 and ended in April 2019.

设计、背景和参与者

2016年1月至2017年7月，香港大学眼科中心以人群为基础的儿童眼健康研究连续招募6至8岁的儿童。所有参与者都接受了详细的眼科检查。脉络膜厚度的测量采用扫描源光学相干断层扫描，内置软件自动分割脉络膜层，分析其地形图像。二手烟史是通过问卷调查获得的。在控制混杂因素的情况下，对脉络膜厚度与间接暴露在二手烟环境之间的相关性进行了多元线性回归分析。分析开始于2018年7月，结束于2019年4月。

Main Outcomes and Measurements

The association between children’s choroidal thickness and their exposure to secondhand smoking.

主要结果及测量方法

儿童脉络膜厚度与暴露在二手烟环境之间的关系。

Results

Of 1400 children, 941 (67.2%) had no exposure to secondhand smoking, and 459 (32.8%) had exposure to secondhand smoking. The mean (SD) age was 7.65 (1.09) years for children in the nonexposure group and 7.54 (1.11) years for children in the exposure group. After adjustment for age, sex, body mass index, axial length, and birth weight, exposure to secondhand smoking was associated with a thinner choroid by 8.3 μm in the central subfield, 7.2 μm in the inner inferior, 6.4 μm in the outer inferior, 6.4 μm in the inner temporal, and 7.3 μm in the outer temporal. Choroidal thinning with also associated with increased number of family smokers and increased quantity of secondhand smoking. An increase of 1 family smoker was associated with choroidal thinning 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, and 6.55 μm in the outer nasal. An increase of exposure to 1 secondhand cigarette smoke per day was associated with choroidal thinning by 0.54 μm in the central subfield, 0.42 μm in the inner temporal, and 0.47 μm in the outer temporal.

结果

在1400名儿童中，941人(67.2%)没有接触过二手烟，459人(32.8%)接触过二手烟。未暴露组儿童的平均年龄为7.65(1.09)岁，暴露组儿童的平均年龄为7.54(1.11)岁。经年龄、性别、身体质量指数、眼轴长度和出生体重调整后，暴露在二手烟环境会使脉络膜中央区变薄8.3μm、内下区变薄7.2μm、外下区变薄6.4μm、内颞区变薄6.4μm、外颞区变薄7.3μm。脉络膜变薄还与家庭吸烟者数量增加和二手烟数量增加有关。每增加1名家庭吸烟者，脉络膜中心区变薄7.86μm，外上区变薄4.51μm，内下区变薄6.23μm，外下区变薄5.59μm，内鼻区变薄6.06μm，外鼻区变薄6.55μm。每天增加1支二手烟的暴露量，会使脉络膜中央区变薄0.54μm，内颞区变薄0.42μm，外颞区变薄0.47μm。

Conclusions and Relevance

This investigation showed that exposure to secondhand smoking in children was associated with choroidal thinning along with a dose-dependent effect. These results support evidence regarding the potential hazards of secondhand smoking to children.

结论和意义

本研究显示，儿童接触二手烟与脉络膜变薄及剂量依赖效应有关。这些结果支持了有关二手烟对儿童潜在危害的证据。

香港中文大学眼科中心的研究人员对1400名6至8岁的儿童进行了研究，已确定接触二手烟的儿童是否也有类似的损伤。他们发现，与没有接触过香烟的儿童相比，周围有烟雾的儿童的脉络膜要薄得多。这种差异约为6至8μm。

同样重要的是，数据显示，儿童的脉络膜变薄随着吸烟家庭成员的数量和每天吸烟的数量的增加而增加。虽然这些相对较小的变化对儿童未来眼睛健康的长期影响仍有待确定，但这项研究表明，早期吸烟可能对以后生活中出现的慢性疾病产生影响。

2015年12月28日，中国疾病预防控制中心发布《2015中国成人烟草调查报告》，报告称，中国人群吸烟率为27.7%，其中男性吸烟率为52.1%，中国吸烟人数高达3.16亿，占世界吸烟总人数的三分之一。

2013年，国家卫生计生委办公厅报道，约有7.4亿不吸烟者遭受二手烟暴露的危害。

二手烟是一个严重的公共健康问题，已经确定这是视力下降的一个危险因素。当然二手烟的危害不仅于此。

再次，呼吁广大群众积极响应国家卫生计生委《公共场所控制吸烟条例》。勿在公众场所吸烟，还孩子一片光明未来。

关爱视觉健康，呵护心灵之窗