Decline in Kidney Function among Apparently Healthy Young Adults at Risk of Mesoamerican Nephropathy.

Abstract

<b>Background</b> Epidemic levels of CKD of undetermined cause, termed Mesoamerican nephropathy in Central America, have been found in low- and middle-income countries. We investigated the natural history of, and factors associated with, loss of kidney function in a population at high risk for this disease.<b>Methods</b> We conducted a 2-year prospective, longitudinal study with follow-up every 6 months in nine rural communities in northwestern Nicaragua and included all men (<i>n</i>=263) and a random sample of women (<i>n</i>=87) ages 18-30 years old without self-reported CKD, diabetes, or hypertension. We used growth mixture modeling to identify subgroups of eGFR trajectory and weighted multinomial logistic regression to examine associations with proposed risk factors.<b>Results</b> Among men, we identified three subpopulations of eGFR trajectory (mean baseline eGFR; mean eGFR change over follow-up): 81% remained stable (116 ml/min per 1.73 m²; -0.6 ml/min per 1.73 m² per year), 9.5% experienced rapid decline despite normal baseline function (112 ml/min per 1.73 m²; -18.2 ml/min per 1.73 m² per year), and 9.5% had baseline dysfunction (58 ml/min per 1.73 m²; -3.8 ml/min per 1.73 m² per year). Among women: 96.6% remained stable (121 ml/min per 1.73 m²; -0.6 ml/min per 1.73 m² per year), and 3.4% experienced rapid decline (132 ml/min per 1.73 m²; -14.6 ml/min per 1.73 m² per year; <i>n</i>=3 women). Among men, outdoor and agricultural work and lack of shade availability during work breaks, reported at baseline, were associated with rapid decline.<b>Conclusions</b> Although Mesoamerican nephropathy is associated with agricultural work, other factors may also contribute to this disease.