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Lower parental education level, an indicator of lower familial SES during fetal development and childhood, is linked to lower nutrient intake, higher exposure to environmental toxicants, more psychological stressors, and reduced access to high-quality parental care, all factors known to increase the likelihood of adverse health outcomes in adulthood, including worse kidney health and functioning. This study examined the association between parental education and longitudinal changes in kidney function across ten years among diverse American adults. Further, we tested if this association was conditional on race.
Data were from 640 Non-Hispanic (NH) Black and white adults (ages at baseline = 35-83; NH Black = 111) who completed the longitudinal biomarker assessment protocols (baseline = 2004-2009; follow-up = 2016-2021) as part of the Midlife in the United States (MIDUS) study (mean follow-up = 11.61 years). Kidney function was based on serum creatinine-based estimated glomerular filtration rate (CKD-EPI formula without race adjustment). Parental education was divided into lower (no HS degree) or higher (HS degree or higher). Analysis was adjusted for age, sex, follow-up duration, smoking status, medication status, and major cardiometabolic risk factors (obesity, hypertension, and diabetes).
The mean decline in eGFR across a decade was -10.49 mL/min/1.73 m^2. The mean declines in eGFR were steeper among NH Black (-13.72 mL/min/1.73 m^2) relative to NH white (-9.58 mL/min/1.73 m^2) participants. About one-third of the participants (34.7%) reported that their parents did not graduate from high school. Within the NH Black group, more than half (53.1%) reported that their parents did not have a high school diploma, while within the NH white group, only one-third reported that their parents did not graduate from high school (31.3%). In the fully adjusted model, parental education was not significantly associated with declines in eGFR across a decade (b = 1.66, SE = 1.42, p = .24). However, we found a significant interaction between parental education and race on declines in eGFR across a decade (b = 7.31, SE = 3.50, p = .037). Lower parental education was significantly associated with faster declines in eGFR among Black (b = 7.57, SE = 3.16, p = .017) but not among white (b = 0.26, SE = 1.56, p = .87) participants.
Our findings indicate that the long arm of childhood socioeconomic disadvantage on worse kidney functioning across adulthood was conditional on race. NH Black participants who grew up in socioeconomically disadvantaged conditions are at risk for accelerated declines in eGFR, which is a robust risk factor for CKD. Future research should investigate the life course biological, psychological, and social pathways to identify potential intervention factors that can mitigate the negative impact of early life socioeconomic disadvantage on worse kidney functioning among diverse populations.