Mortality, ethnicity, and country of birth on a national scale, 2001–2013: A retrospective cohort (Scottish Health and Ethnicity Linkage Study)

BackgroundMigrant and ethnic minority groups are often assumed to have poor health relative to the majority population. Few countries have the capacity to study a key indicator, mortality, by ethnicity and country of birth. We hypothesized at least 10% differences in mortality by ethnic group in Scotland that would not be wholly attenuated by adjustment for socio-economic factors or country of birth.Methods and findingsWe linked the Scottish 2001 Census to mortality data (2001–2013) in 4.62 million people (91% of estimated population), calculating age-adjusted mortality rate ratios (RRs; multiplied by 100 as percentages) with 95% confidence intervals (CIs) for 13 ethnic groups, with the White Scottish group as reference (ethnic group classification follows the Scottish 2001 Census). The Scottish Index of Multiple Deprivation, education status, and household tenure were socio-economic status (SES) confounding variables and born in the UK or Republic of Ireland (UK/RoI) an interacting and confounding variable. Smoking and diabetes data were from a primary care sub-sample (about 53,000 people). Males and females in most minority groups had lower age-adjusted mortality RRs than the White Scottish group. The 95% CIs provided good evidence that the RR was more than 10% lower in the following ethnic groups: Other White British (72.3 [95% CI 64.2, 81.3] in males and 75.2 [68.0, 83.2] in females); Other White (80.8 [72.8, 89.8] in males and 76.2 [68.6, 84.7] in females); Indian (62.6 [51.6, 76.0] in males and 60.7 [50.4, 73.1] in females); Pakistani (66.1 [57.4, 76.2] in males and 73.8 [63.7, 85.5] in females); Bangladeshi males (50.7 [32.5, 79.1]); Caribbean females (57.5 [38.5, 85.9]); and Chinese (52.2 [43.7, 62.5] in males and 65.8 [55.3, 78.2] in females). The differences were diminished but not eliminated after adjusting for UK/RoI birth and SES variables. A mortality advantage was evident in all 12 minority groups for those born abroad, but in only 6/12 male groups and 5/12 female groups of those born in the UK/RoI. In the primary care sub-sample, after adjustment for age, UK/RoI born, SES, smoking, and diabetes, the RR was not lower in Indian males (114.7 [95% CI 78.3, 167.9]) and Pakistani females (103.9 [73.9, 145.9]) than in White Scottish males and females, respectively. The main limitations were the inability to include deaths abroad and the small number of deaths in some ethnic minority groups, especially for people born in the UK/RoI.ConclusionsThere was relatively low mortality for many ethnic minority groups compared to the White Scottish majority. The mortality advantage was less clear in UK/RoI-born minority group offspring than in immigrants. These differences need explaining, and health-related behaviours seem important. Similar analyses are required internationally to fulfil agreed goals for monitoring, understanding, and improving health in ethnically diverse societies and to apply to health policy, especially on health inequalities and inequities.

研究背景
移民与少数族裔群体通常被认为相较于主体人口健康状况更差。鲜有国家具备按族裔与出生国家研究核心指标——死亡率的能力。本研究假设：苏格兰不同族裔群体间的死亡率差异至少可达10%，且该差异无法通过调整社会经济因素或出生国家完全消除。

研究方法与结果
我们将2001年苏格兰人口普查数据与462万（占预估总人口91%）人群的2001–2013年死亡率数据进行关联，以白人苏格兰族为参照组，对13个族裔群体计算年龄标化死亡率比（mortality rate ratios, RRs；以百分比形式乘以100）及95%置信区间（confidence intervals, CIs），族裔分类标准遵循2001年苏格兰人口普查方案。苏格兰多重贫困指数（Scottish Index of Multiple Deprivation）、受教育程度与住房保有状况作为社会经济地位（socio-economic status, SES）混杂变量，而出生于英国或爱尔兰共和国（UK/RoI）则作为交互混杂变量。吸烟与糖尿病数据来自一个约5.3万人的基层医疗亚样本。
多数少数族裔群体的男性与女性的年龄标化死亡率比均低于白人苏格兰族参照组。95%置信区间提供了充分证据，表明以下族裔群体的死亡率比较参照组低10%以上：其他英裔白人（男性72.3 [95%CI 64.2, 81.3]，女性75.2 [68.0, 83.2]）；其他白人（男性80.8 [72.8, 89.8]，女性76.2 [68.6, 84.7]）；印度裔（男性62.6 [51.6, 76.0]，女性60.7 [50.4, 73.1]）；巴基斯坦裔（男性66.1 [57.4, 76.2]，女性73.8 [63.7, 85.5]）；孟加拉裔男性（50.7 [32.5, 79.1]）；加勒比裔女性（57.5 [38.5, 85.9]）；以及华裔（男性52.2 [43.7, 62.5]，女性65.8 [55.3, 78.2]）。在调整出生于英国/爱尔兰共和国情况与社会经济地位变量后，上述差异有所减小但并未完全消除。
对于海外出生的少数族裔群体，12个群体均表现出死亡率优势；而对于在英国/爱尔兰共和国出生的群体，仅6/12的男性族裔群体与5/12的女性族裔群体存在该优势。在基层医疗亚样本中，在调整年龄、出生于英国/爱尔兰共和国情况、社会经济地位、吸烟与糖尿病状况后，印度裔男性（114.7 [95%CI 78.3, 167.9]）与巴基斯坦裔女性（103.9 [73.9, 145.9]）的死亡率比分别未低于白人苏格兰族男性与女性。本研究的主要局限在于无法纳入境外死亡数据，且部分少数族裔群体的死亡人数较少，尤其是在英国/爱尔兰共和国出生的群体。

研究结论
相较于白人苏格兰族主体人口，多数少数族裔群体的死亡率相对更低。在英国/爱尔兰共和国出生的少数族裔后代中，死亡率优势不如移民群体显著。上述差异尚需进一步阐释，而健康相关行为似乎是关键影响因素。为实现监测、理解并改善多元族裔社会健康状况的既定目标，同时为健康政策（尤其是针对健康不平等与不公平性的政策）提供依据，国际范围内亟需开展类似研究分析。