Mitchell Richard, Popham Frank
Public Health and Health Policy, University of Glasgow, Glasgow, UK.
Lancet. 2008 Nov 8;372(9650):1655-60. doi: 10.1016/S0140-6736(08)61689-X.
Studies have shown that exposure to the natural environment, or so-called green space, has an independent effect on health and health-related behaviours. We postulated that income-related inequality in health would be less pronounced in populations with greater exposure to green space, since access to such areas can modify pathways through which low socioeconomic position can lead to disease.
We classified the population of England at younger than retirement age (n=40 813 236) into groups on the basis of income deprivation and exposure to green space. We obtained individual mortality records (n=366 348) to establish whether the association between income deprivation, all-cause mortality, and cause-specific mortality (circulatory disease, lung cancer, and intentional self-harm) in 2001-05, varied by exposure to green space measured in 2001, with control for potential confounding factors. We used stratified models to identify the nature of this variation.
The association between income deprivation and mortality differed significantly across the groups of exposure to green space for mortality from all causes (p<0.0001) and circulatory disease (p=0.0212), but not from lung cancer or intentional self-harm. Health inequalities related to income deprivation in all-cause mortality and mortality from circulatory diseases were lower in populations living in the greenest areas. The incidence rate ratio (IRR) for all-cause mortality for the most income deprived quartile compared with the least deprived was 1.93 (95% CI 1.86-2.01) in the least green areas, whereas it was 1.43 (1.34-1.53) in the most green. For circulatory diseases, the IRR was 2.19 (2.04-2.34) in the least green areas and 1.54 (1.38-1.73) in the most green. There was no effect for causes of death unlikely to be affected by green space, such as lung cancer and intentional self-harm.
Populations that are exposed to the greenest environments also have lowest levels of health inequality related to income deprivation. Physical environments that promote good health might be important to reduce socioeconomic health inequalities.
研究表明，接触自然环境，即所谓的绿地，对健康及与健康相关的行为具有独立影响。我们推测，在接触绿地更多的人群中，与收入相关的健康不平等现象会不那么明显，因为进入这些区域可以改变低社会经济地位导致疾病的途径。
我们根据收入匮乏程度和接触绿地的情况，将英格兰退休年龄以下的人口（n = 40813236）分组。我们获取了个体死亡记录（n = 366348），以确定2001 - 2005年间收入匮乏、全因死亡率以及特定病因死亡率（循环系统疾病、肺癌和故意自伤）之间的关联，是否因2001年测量的接触绿地情况而异，并对潜在混杂因素进行了控制。我们使用分层模型来确定这种差异的性质。
在所有原因导致的死亡率（p < 0.0001）和循环系统疾病死亡率（p = 0.0212）方面，收入匮乏与死亡率之间的关联在不同绿地接触组之间存在显著差异，但在肺癌或故意自伤方面不存在显著差异。在最绿化地区生活的人群中，与收入匮乏相关的全因死亡率和循环系统疾病死亡率方面的健康不平等程度较低。在绿化程度最低的地区，收入最匮乏四分位数人群与最不匮乏人群相比，全因死亡率的发病率比值比（IRR）为1.93（95%CI 1.86 - 2.01），而在绿化程度最高的地区为1.43（1.34 - 1.53）。对于循环系统疾病，在绿化程度最低的地区，IRR为2.19（2.04 - 2.34），在绿化程度最高的地区为1.54（1.38 - 1.73）。对于不太可能受绿地影响的死因，如肺癌和故意自伤，则没有影响。
接触最绿化环境的人群与收入匮乏相关的健康不平等程度也最低。促进健康的物理环境对于减少社会经济健康不平等可能很重要。
