Depression was ranked as the second leading cause of global burden of disease in 2010 [1, 2], and expected to be the first by 2030. In particular, elderly have been proved to be of great risk in developing depressive symptoms [3–5], because of complex interactions among genetic vulnerabilities, cognitive diathesis, age-associated neurobiological changes, and stressful events . Particularly, in modern society of China, along with increasing migrant labor, more elderly became empty nest. Living without daily care and social support from family members, things became even worse to the elderly . As shown in one study, overall prevalence of depression among Chinese older adults have reached about 22.6%, and act in a growing trend . Furthermore, it has been testified that suicidal rate among depressed elderly was significantly higher than those who not . In a nutshell, elderly depressive symptoms are an important issue deserves more public attention.
When it comes to the risk factors associated with elderly depressive symptoms, the neighborhood quality is the one that have attracted many attentions. Generally speaking, the neighborhood quality is an indicator which suggests individual’s satisfaction towards their neighbors and the community they live in , and can be measured by physical and social features [10, 11]. Physical features of the neighborhood quality encompass physical condition of housing [12, 13], access to basic resources [14, 15], dirty-looking , noise , green space  and so on. Social features consist of community-level socioeconomic status [19, 20], social process (including social cohesion, crime, disorder, organizational participation and so on) [21–23], and the relationship of neighborhood residents .
Prior studies have noted that neighborhood quality was associated with self-perceived depressive symptoms greatly, even adjusting for demographic and other individual level factors . For example, neighborhood social cohesion, referring to norms of trust, solidarity and reciprocity, have been extensively examined in relation to depressive symptoms among English older adults . Meanwhile, higher level of community safety has been found to be a protective factor in reducing elderly depressive symptoms, for it enables more physical and social activities  and reduces safety concern . Also, the cleanness of community environment examined to be a protective factor in reducing elderly depressive symptoms . However, few of these studies have been conducted in Chinese social settings. Since Chinese older adults engaged more in core families and tied loosely with communities, whether the influences from communities are valid is still unknown. More studies are in need.
Additionally, from the perspective of life span theory, childhood neighborhood quality may have potential influence on individuals’ later mental health status until elderly life [28–30]. The reason maybe as following: Firstly, childhood neighborhood conditions represent the lower socioeconomic status, thus leading to more negative life event and increased mental health disorders . Secondly, individuals with poor childhood neighborhood experience may be more prone to experiencing negative emotional states than others, and stress related to neighborhood condition accumulated over the early part of life may affect health outcomes in the future [33, 34]. Finally, individuals lived with poor childhood neighborhood may be less likely to engage in healthy behaviors, such as exercising, not drinking smoking, which was related to depressive symptoms . Accordingly, this study assumed that poor neighborhood quality during childhood will leads to an accumulation of substantial health disadvantages by adulthood, and increases depressive risks in old age.
Furthermore, when it comes to the relationship between neighborhood quality during childhood and depressive symptoms in later life, some social demographic characteristics do matters. Gender difference was discussed but with different answers. Some studies suggested that women may be more vulnerable than men to certain aspects of the neighborhood environment due to differences in social roles [34, 35], while other studies claimed that no significant gender differences exists . However, none of them was conducted among older adults, and whether gender difference is significant in association between elderly depressive symptoms and neighborhood quality during childhood is still unclear. Besides, education was been proved as an important factor related to depressive symptoms in previous studies . In light of the growing enthusiasm for education as a policy lever to improve population health, whether the association between childhood neighborhood and depressive symptoms was moderate with different education level is need of further examination.
Therefore, the objectives of this study were to: 1) determine the association between the perception of neighborhood quality during childhood and depressive symptoms among Chinese older adults; 2) explore whether there is gender difference exists in the association mentioned above; 3) examine the interaction effect of education, if exists, within the association between the perception of childhood neighborhood quality and depressive symptoms among old people.