Lifestyle factors and indices of kidney function in the Framingham Heart Study

Authors: FOSTER, MEREDITH - Tufts University; HWANG, SHIH-JEN - National Institutes Of Health (NIH); MASSARO, JOSEPH - Boston University; JACQUES, PAUL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; FOX, CAROLINE - National Institutes Of Health (NIH); CHU, AUDREY - National Institutes Of Health (NIH)

Submitted to: The American Journal of Nephrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2015
Publication Date: 5/20/2015
Citation: Foster, M.C., Hwang, S., Massaro, J.M., Jacques, P.F., Fox, C.S., Chu, A.Y. 2015. Lifestyle factors and indices of kidney function in the Framingham Heart Study. The American Journal of Nephrology. 41:267-274. https://doi.org/10.1159/000430868.

Interpretive Summary: Chronic kidney disease (CKD) affects over 26 million adults in the United States, and its incidence is increasing. CKD is a risk factor for cardiovascular disease morbidity and mortality, and several established cardiovascular risk factors are also risk factors for CKD, including diabetes, hypertension, and obesity. Obesity is of particular interest in relation to CKD. In addition to being an established risk factor for the development of cardiovascular and metabolic diseases, obesity is a common condition in the United States that can be modified through lifestyle interventions. Growing evidence shows that obesity may be linked to CKD; thus, lifestyle factors such as physical activity, smoking, and diet that are associated with obesity may also be associated with developing CKD. We examined participants in the Framingham Offspring Study exams 7 and 8 in order to determine how lifestyle factors may be associated with glomerular filtration rate (eGFR,) a measure of kidney function that can indicate kidney disease. We did not observe any associations between eGFR and physical activity, smoking status, or alcohol intake. However, our results did show that better diet quality was associated with a decreased risk of having eGFR levels indicative of CKD. In other words, while our study cannot specifically link healthy diet to lower risk of CKD, it shows that future research should further examine the link between healthy diet and reduced risk of kidney disease.

Technical Abstract: Background and objectives: Lifestyle characteristics are modifiable factors that could be targeted as part of chronic kidney disease (CKD) prevention. We sought to determine the association of lifestyle characteristics with incident estimated glomerular filtration rate (eGFR)<60mL/min/1.73m2 and rapid eGFR decline in older adults in the United States. Methods: Prospective cohort study of Framingham Offspring participants with baseline eGFR<60mL/min/1.73m2 (n=1,802) who attended the seventh (1998-2001; baseline) and eighth (2005-2008; follow-up) examinations (mean age=59years, 54.8% women). Predictors included measures of diet quality, physical activity, alcohol intake, and current smoking status assessed during baseline. Outcomes were based on creatinine-based eGFR at baseline and follow-up and included incident eGFR<60mL/min/1.73m2 (at follow-up) and rapid eGFR decline (annual eGFR decrease >/= 3mL/min/1.73m2). Results: Over an average follow-up of 6.6 years, 9.5% (n=171) of participants developed incident eGFR<60. A trend was observed across quartiles of diet quality, with higher levels of diet quality associated with a decreased odds ratio (OR) of incident eGFR<60 (p trend=0.045). Higher diet quality was associated with decreased odds of rapid eGFR decline (p trend=0.03) and was attenuated with additional adjustment (p trend=0.07). In sensitivity analysis for rapid eGFR decline using a secondary definition (annual eGFR decrease >/=3 and incident eGFR<60), diet associations remained significant with additional adjustment (p trend=0.04). No associations were observed with physical activity, smoking status, or alcohol intake with incident eGFR<60 or rapid eGFR decline (all p>0.19). Conclusions: Higher diet quality may be associated with a decreased risk of incident eGFR<60mL/min/1.73m2, and rapid eGFR decline. Whether adherence to a healthy diet can prevent reduction in kidney function warrants further study.