Association of dwelling floor level and health : a systematic review

Abstract

Objective To review and summarize the latest findings on the relationship between dwelling floor level and health conditions.

Background Hong Kong is famous for its high population density and high-rise architectural characteristic. Many residents in Hong Kong live in high floor levels of high-rise buildings. Thus, people are more concerned about the health related to dwelling floor level but there is no consensus of whether and what kind of association exists between health and floor-of-residence so far.

Methods A literature review was conducted by using PubMed, ISI Web of Science and China Journal Net (CNKI). Key words were used in three databases to identify studies. A further literature search was processed by citation checking, called snowballing which involves recursively pursuing relevant references cited in already-retrieved articles and including them to the search results. Studies with estimates of association between floor of residence and several health conditions, including psychological problems such as stress and depression, suicide, respiratory diseases such as tuberculosis, and cardiovascular diseases, were deemed eligible. Papers on the relationship of floor-of-residence with air pollution and noise were also included for review even if these papers did not discuss any particular health conditions. Studies in English or Chinese published from 1st January 1960 to 15th July 2015 would be included in the systematic review. Results Three thousand and forty studies were identified by keywords. Seven of them were included after screening the abstracts. Five additional eligible studies were included by citation checking called snowballing. Among the 12 studies included for final review, 6 were mainly on psychological health conditions, 3 on respiratory or cardiovascular diseases, and 3 others on air pollution and noise related health conditions. Among the studies exploring the effect of dwelling floor level on mental problems (psychological health include psychoneuroses, emotional illness and hostility, social connecting ability, depression, strain and independence rate of daily function), 5 of them stated that dwelling floor level had positive association with mental problems and another study reported negative association among men but positive association among women. Two studies found that floor of residence tended to have strong negative exponential association with the incidence of tuberculosis (TB), with R^2 = 0.8302 and p<0.05. One study reported that the hazard ratio for respiratory diseases comparing ground floor and eighth floor above is 1.40, 95% CI = (1.11, 1.77), for cardiovascular disease is 1.35, 95% CI = (1.22, 1.49). For air pollutant, one study showed that indoor black carbon (BC) and Σ8PAHnonvolatile are negatively associated with floor. Another study reported an inverted u-relation between PM2.5 and floor level (p<0.05). For noise, one identified study indicated that floor level has negative association with traffic noise, with R^2 = 0.9331.

Conclusion The results of 12 studies are inconsistent. Heterogeneity of studies characteristics makes it hard to draw a clear-cut conclusion. Confounding, bias, generalizability problem exist in the studies. The number of studies is not sufficient for a quantitative meta-analysis. The association between dwelling floor level and health is still uncertain.