Increased body fat rather than body weight has harmful effects on 4-year changes of renal function in the general elderly population with a normal or mildly impaired renal function

Abstract

BackgroundWith increasing age, body fat increases and muscle mass reduces. Even people with a normal weight may have a higher percentage of body fat. The aim of this study is to investigate the association between increased body fat and renal function decline (RFD) in the general elderly population with normal or mildly impaired renal function.MethodWe conducted a prospective study of 615 healthy individuals in the general Korean population aged ≥60 years who participated in two health screening check-ups separated by a 4-year period. Obesity was defined as the highest sex-specific tertiles of the percentage body fat (PBF). The main outcome was changes of estimated glomerular filtration rate (eGFR) during the 4 years. Significant RFD was defined as a decrease of eGFR over the upper quartile (≤−2.1% per year).ResultsThe mean age was 67.2±6.6 years. The median value of the absolute decline in the eGFR and the percent change was −3.0 mL/minute/1.73 m2 and −0.87%/year in men and −3.1 mL/minute/1.73 m2 and −0.89%/year in women, respectively. When stratified by sex-specific PBF tertiles, pronounced differences were observed in both sexes; those at the highest tertile of PBF showed the greatest decline in eGFR. Even after adjustments for traditional risk factors of RFD, PBF was independently associated with eGFR changes (β=−0.181; P<0.001). In addition, the harmful effect of a high PBF was consistently found in subjects with a normal weight, too (β=−0.141; P=0.006). Cases of significant RFD occurred in 181 participants (29.4%), and the risk was higher in obese participants as compared with the nonobese participants. The odd ratios (95% confidence interval) for significant RFD were 2.76 (1.28–7.74) in men and 2.02 (1.06–4.43) in women in a whole population and 3.15 (1.03–18.52) in men and 1.44 (1.01–3.28) in women with a normal weight, respectively.ConclusionAmong the elderly population without comorbidities, increased body fat has a harmful effect on RFD, irrespective of body weight.

Risk factors for renal function decline in adults with normal kidney function: a 7-year cohort study

“…Our results suggested that control of obesity and abdominal obesity was required to reduce the risk of RFD; however, abdominal obesity may possibly be a more important risk factor for RFD. Consistently, Kim et al 22 also reported that percentage body fat was associated with eGFR changes, even in participants with a normal weight.…”

Progression of Kidney Disease in Indigenous Australians: The eGFR Follow-up Study

“…Elevated CRP has been previously reported to be strongly associated with central obesity in remote Aboriginal populations (25), which in turn may be associated with hyperfiltration and thus eGFR decline. The potential role of central obesity is supported by a recent report that percentage body fat (rather than weight) was independently associated with eGFR decline in 615 healthy Koreans (26). Elevated CRP is a marker of inflammation and was independently associated with eGFR decline in the Multi-Ethnic Study of Atherosclerosis (27).…”

The A Body Shape Index Might Be a Stronger Predictor of Chronic Kidney Disease Than BMI in a Senior Population

“…For decades, the BMI-based evaluation of obesity was universally used to investigate the association between obesity and various chronic diseases, and its validity and reliability have been adequately verified [ 32 , 33 ]. However, recent studies indicated that higher fat mass is closely linked to an increased risk of chronic diseases [ 13 , 34 , 35 ]. Additionally, abdominal fat accumulation is recognized to be incredibly perilous [ 36 , 37 , 38 ].…”