**Background:** Self-perceived health (SPH) is a validated, widely used measure of an individual's overall subjective perception of their physical and mental health, recognized by the WHO as one of the best health indicators. As rural-to-urban migration increases in South Africa, informal settlement dwellers face heightened health risks due to overcrowding, poor housing, inadequate sanitation, and lack of basic services. While previous studies have examined SPH determinants in general populations or specific communities, no nationally representative study had assessed factors associated with deteriorated SPH specifically among informal settlement dwellers in South Africa. This study aimed to fill that gap by exploring determinants of deteriorated SPH using data from the first national Informal Settlements Survey.
**Methods:** Data came from the 2015 Human Sciences Research Council (HSRC) Informal Settlements Survey, which employed stratified random sampling. A total of 75 informal settlements targeted for upgrading were visited across South Africa, and 2380 household heads were interviewed using a semi-structured questionnaire. After excluding respondents who did not answer the main outcome question, the final analytic sample was 2242. The outcome variable was SPH compared to one year prior, dichotomized as deteriorated (much worse/somewhat worse) vs. better/about the same (somewhat better, much better, about the same). Explanatory variables included demographic factors (sex, age, marital status), socioeconomic factors (education, employment, monthly household income, food insecurity, Living Standard Measure), and health/behavioral factors (illness/injury in past month, tobacco use, alcohol use, drug use). Multivariate logistic regression and multinomial logistic regression were performed using Stata 15.0 with survey weights applied. The proportional odds assumption was violated, justifying the use of multinomial logistic regression with better/improved SPH and neutral SPH as separate base categories.
**Key Results:** The sample was 54.5% male and 45.5% female, with the dominant age group being 30–39 years (approximately 30%). In multivariate logistic regression, informal settlement dwellers aged 30–39 years were significantly less likely to report deteriorated SPH compared to those aged 18–29 (OR = 0.332, 95% CI [0.131–0.840], p < 0.05). Those with household income of ZAR 5501 or more per month were significantly less likely to report deterioration than those in the lowest income band (ZAR 0–2000) (OR = 0.365, 95% CI [0.144–0.922], p < 0.05). Drug users were significantly less likely to report deteriorated SPH (OR = 0.069, 95% CI [0.020–0.240], p < 0.001). Conversely, those who reported always running out of food had significantly higher odds of deteriorated SPH (OR = 3.120, 95% CI [1.258–7.737], p < 0.05), and those who suffered illness or injury in the past month had significantly higher odds (OR = 3.645, 95% CI [2.147–6.186], p < 0.001). In multinomial logistic regression with neutral SPH as the base category, employed residents were significantly more likely to report deteriorated SPH than unemployed residents (OR = 1.830, 95% CI [1.001–3.347], p = 0.05). Household income was not significant in the multinomial models.
**Clinical Implications:** The study identifies both structural factors (income, employment, food insecurity) and individual factors (age, drug use, illness/injury) as key determinants of deteriorated SPH among informal settlement dwellers. The paradoxical finding that drug users were less likely to report deteriorated SPH may reflect inebriation at the time of interview masking true perceptions, or the very small number of drug users reporting deterioration. Food insecurity and recent illness/injury emerged as the strongest predictors of deteriorated SPH, with odds ratios above 3.0. The authors recommend that deteriorated or poor SPH be considered as an indicator of poor health status where physical health examinations are not feasible, and that these key factors be incorporated into planning and policy development for informal settlement upgrading. Limitations include potential recall and social desirability bias, and a sample skewed toward unemployed and lower-income groups, which may overestimate poor SPH.