Relationships between social isolation, neighborhood poverty, and cancer mortality in a population-based study of US adults

• Published in: PloS one 2017-03, Vol.12 (3), p.e0173370-e0173370
• Main Authors: Fleisch Marcus, Andrea, Illescas, Alex H, Hohl, Bernadette C, Llanos, Adana A M
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Adults; Aged; Aged, 80 and over; Analysis; Biology and Life Sciences; Cancer; Cancer patients; Computer and Information Sciences; Earth Sciences; Economic aspects; Female; Females; Hazards; Health aspects; Health disparities; Health risks; Health Surveys; Humans; Male; Medicine and Health Sciences; Middle Aged; Minority & ethnic groups; Mortality; Neoplasms - epidemiology; Neoplasms - mortality; Nutrition; Nutrition Surveys; People and Places; Population studies; Population Surveillance; Population-based studies; Poverty; Proportional Hazards Models; Research and Analysis Methods; Residence Characteristics; Risk analysis; Risk factors; Sex; Social aspects; Social interactions; Social Isolation; Social networks; Social Sciences; Social support; Socioeconomic Factors; Socioeconomics; Statistical models; United States; United States - epidemiology; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0173370

Social isolation is an important determinant of all-cause mortality, with evidence suggesting an association with cancer-specific mortality as well. In this study, we examined the associations between social isolation and neighborhood poverty (independently and jointly) on cancer mortality in a population-based sample of US adults. Using data from the Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994), NHANES III Linked Mortality File (through 2011) and 1990 Census, we estimated the relationship between social isolation and high neighborhood poverty and time-to-cancer death using multivariable-adjusted Cox proportional hazards models. We examined the associations of each factor independently and explored the multiplicative and additive interaction effects on cancer mortality risk and also analyzed these associations by sex. Among 16 044 US adults with 17-23 years of follow-up, there were 1133 cancer deaths. Social isolation (HR 1.25, 95% CI: 1.01-1.54) and high neighborhood poverty (HR 1.31, 95% CI: 1.08-1.60) were associated with increased risk of cancer mortality adjusting for age, sex, and race/ethnicity; in sex-specific estimates this increase in risk was evident among females only (HR 1.39, 95% CI: 1.04-1.86). These associations were attenuated upon further adjustment for socioeconomic status. There was no evidence of joint effects of social isolation and high neighborhood poverty on cancer mortality overall or in the sex-stratified models. These findings suggest that social isolation and higher neighborhood poverty are independently associated with increased risk of cancer mortality, although there is no evidence to support our a priori hypothesis of a joint effect.