Background

There are few quantitative studies into the effect of comprehensive smoke-free legislation on neonatal and infant mortality in middle-income countries. We aimed to estimate the effects of implementing comprehensive smoke-free legislation on neonatal mortality and infant mortality across all middle-income countries.

Methods

We applied the synthetic control method using 1990–2018 country-level panel data for 106 middle-income countries from the WHO, World Bank, and Penn World datasets. Outcome variables were neonatal (age 0–28 days) mortality and infant (age 0–12 months) mortality rates per 1000 livebirths per year. For each middle-income country with comprehensive smoke-free legislation, a synthetic control country was constructed from middle-income countries without comprehensive smoke-free legislation, but with similar prelegislation trends in the outcome and predictor variables. Overall legislation effect was the mean average of country-specific effects weighted by the number of livebirths. We compared the distribution of the legislation effects with that of the placebo effects to assess the likelihood that the observed effect was related to the implementation of smoke-free legislation and not merely influenced by other processes.

Findings

31 (29%) of 106 middle-income countries introduced comprehensive smoke-free legislation and had outcome data for at least 3 years after the intervention. We were able to construct a synthetic control country for 18 countries for neonatal mortality and for 15 countries for infant mortality. Comprehensive smoke-free legislation was followed by a mean yearly decrease of 1·63% in neonatal mortality and a mean yearly decrease of 1·33% in infant mortality. An estimated 12 392 neonatal deaths in 18 countries and 8932 infant deaths in 15 countries were avoided over 3 years following the implementation of comprehensive smoke-free legislation. We estimated that an additional 104 063 infant deaths (including 95 850 neonatal deaths) could have been avoided over 3 years if the 72 control middle-income countries had introduced this legislation in 2015. 220 (43%) of 514 placebo effects for neonatal mortality and 112 (39%) of 289 for infant mortality were larger than the estimated aggregated legislation effect, indicating a degree of uncertainty around our estimates. Sensitivity analyses showed results that were consistent with the main analysis and suggested a dose–response association related to comprehensiveness of the legislation.

Interpretation

Implementing comprehensive smoke-free legislation in middle-income countries could substantially reduce preventable deaths in neonates and infants.

Funding

Dutch Heart Foundation, Lung Foundation Netherlands, Dutch Cancer Society, Dutch Diabetes Research Foundation, Netherlands Thrombosis Foundation, Health Data Research UK.

中文翻译：

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全面无烟立法对 106 个中等收入国家新生儿死亡率和婴儿死亡率的影响：一项综合对照研究

背景

关于全面无烟立法对中等收入国家新生儿和婴儿死亡率影响的定量研究很少。我们旨在评估在所有中等收入国家实施全面无烟立法对新生儿死亡率和婴儿死亡率的影响。

方法

我们使用来自 WHO、世界银行和 Penn World 数据集的 106 个中等收入国家的 1990-2018 年国家级面板数据应用综合控制方法。结果变量是每年每 1000 例活产中的新生儿（0-28 天）死亡率和婴儿（0-12 个月）死亡率。对于每个具有全面无烟立法的中等收入国家，由没有全面无烟立法但在结果和预测变量方面具有相似立法前趋势的中等收入国家构建了一个综合控制国家。总体立法效果是按活产数加权的国家特定效果的平均平均值。

发现

106 个中等收入国家中的 31 个（29%）引入了全面的无烟立法，并且在干预后至少 3 年有结果数据。我们能够为 18 个国家的新生儿死亡率和 15 个国家的婴儿死亡率构建一个综合控制国家。全面的无烟立法之后，新生儿死亡率平均每年下降 1·63%，婴儿死亡率每年平均下降 1·33%。在全面无烟立法实施后的 3 年内，估计有 18 个国家的 12392 名新生儿死亡和 15 个国家的 8932 名婴儿死亡被避免。我们估计，如果 72 个控制性中等收入国家在 2015 年引入这项立法，则本可以在 3 年内避免额外的 104 063 例婴儿死亡（包括 95 850 例新生儿死亡）。514 项安慰剂效应中的 220 项（43%）新生儿死亡率和 289 项婴儿死亡率的 112 项（39%）大于估计的汇总立法效应，表明我们的估计存在一定程度的不确定性。敏感性分析显示的结果与主要分析一致，并提出了与立法全面性相关的剂量反应关联。

解释

在中等收入国家实施全面的无烟立法可以大大减少新生儿和婴儿的可预防死亡。

资金

荷兰心脏基金会、荷兰肺基金会、荷兰癌症协会、荷兰糖尿病研究基金会、荷兰血栓形成基金会、英国健康数据研究中心。