U-shaped association between sleep duration and urinary albumin excretion in Korean adults: 2011-2014 Korea National Health and Nutrition Examination Survey

<div><p>Although sleep duration has been extensively studied in metabolic diseases, few studies have investigated the impact of sleep duration on chronic kidney disease. The aim of this study was to examine the relationship between sleep duration and albuminuria in the general population. Among 24,948 adults who participated in the 2011–2014 KNHANES, a total of 19,994 subjects were included in this analysis. Subjects were categorized into the following five groups according to self-reported sleep duration: less than 5 h, 6 h, 7 h, 8 h, and more than 9 h. The association between sleep duration and urinary albumin-creatinine ratio (UACR) was examined cross-sectionally. Subjects with both short and long sleep durations were significantly associated with higher UACR levels and higher proportions of patients with microalbuminuria (30–299 mg/g) and macroalbuminuria (≥300 mg/g) compared to those with a sleep duration of 7 hours. The U-shaped association between sleep duration and UACR remained significant even after adjustment for potential confounders, including age, sex, body mass index, smoking, alcohol, education, income, exercise, estimated glomerular filtration rate, diabetes mellitus, hypertension and hypercholesterolemia. The U-shaped association is more evident in the subgroup aged 65 or older, or in female subjects. Our findings suggest that both short and long sleep durations have a U-shaped association with UACR levels in the general population, independent of potential confounders.</p></div

Clinical characteristics of study subjects according to sleep duration.

<p>Clinical characteristics of study subjects according to sleep duration.</p

U-shaped association between sleep duration and urinary albumin excretion in Korean adults: 2011-2014 Korea National Health and Nutrition Examination Survey - Fig 1

<p><b>Proportion of patients with microalbuminuria (A) or macroalbuminuria (B) according to sleep duration.</b> Microalbuminuria was defined as 30mg/g≤ urinary albumin-creatinine ratio (UACR) <300 mg/g, and macroalbuminuria was defined as UACR ≥300 mg/g. *<i>P</i> <0.005 vs. sleep duration of 7 hours per day.</p

Adjusted urinary albumin-creatinine ratio (UACR) levels according to sleep duration.

<p>Adjusted urinary albumin-creatinine ratio (UACR) levels according to sleep duration.</p

Odds ratios (95% Cis) for albuminuria according to sleep duration.

<p>Odds ratios (95% Cis) for albuminuria according to sleep duration.</p

Low Vitamin D Status Is Associated with Nonalcoholic Fatty Liver Disease Independent of Visceral Obesity in Korean Adults

<div><p>Objective</p><p>To investigate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and nonalcoholic fatty liver disease (NAFLD) independent of visceral obesity in Koreans and to examine whether the associations differ according to the presence of diabetes or insulin resistance.</p><p>Research Design and Methods</p><p>A total of 1081 adults were enrolled from a population-based cohort in Ansan city. Serum 25(OH)D concentrations were measured in all subjects. Insulin resistance was measured by homeostasis model assessment of insulin resistance (HOMA-IR). Using computed tomography, NAFLD was diagnosed if the liver attenuation index (LAI, the difference between the mean hepatic and splenic attenuation) was <5 Hounsfield Units.</p><p>Results</p><p>In subjects with diabetes (n = 282), 25(OH)D levels were negatively associated with waist circumference, fasting insulin, HOMA-IR, triglyceride levels, and visceral abdominal fat, and were positively associated with LAI after adjusting for age, sex, season, exercise, and vitamin supplementation. In subjects without diabetes, only triglyceride level was negatively associated with 25(OH)D. The adjusted odds ratio (OR) for NAFLD increased sequentially across decreasing quartiles of 25(OH)D in subjects with diabetes even after adjusting for visceral fat [Q1 vs. Q4; OR for NAFLD 2.5 (95% CI:1.0–6.2)]. In contrast, no significant difference in OR was observed in subjects without diabetes. When we classified non-diabetic subjects by HOMA-IR, an increase in the OR for NAFLD across decreasing quartiles of 25(OH)D was observed in the high HOMA-IR (≥2.5) group [n = 207, Q1 vs. Q4; OR 3.8(1.4–10.3)], but not in the low HOMA-IR (<2.5) group [n = 592, OR 0.8 (0.3–1.9)].</p><p>Conclusions</p><p>Low vitamin D status is closely associated with NAFLD, independent of visceral obesity in subjects with diabetes or insulin resistance.</p></div

Correlation plots between log-transformed 25(OH)D and liver attenuation index (LAI) in diabetic (A), non-diabetic (B), non-diabetic, IR+ (C) and non-diabetic, IR- (D) subjects, respectively.

<p>(correlation coefficient (<i>r</i>) and <i>p</i> value (<i>p</i>) of A, B, C, and D: A, <i>r = </i>0.1137, <i>p</i> = 0.057; B, <i>r</i> = −0.0005, <i>p</i> = 0.990; C, <i>r</i> = 0.1535, <i>p</i> = 0.027; D, <i>r</i> = −0.0570, <i>p</i> = 0.167).</p

Odds ratios for NAFLD in subjects with or without diabetes according to the month-matched 25(OH)D quartiles.

<p>Model 1: adjusted for age, sex, exercise, vitamin supplementation, active cancer, recent hospitalization, chronic pulmonary diseases, and cardiovascular diseases.</p><p>Model 2: model 1+ body mass index.</p><p>Model 3: model 1+ visceral abdominal fat.</p><p>Model 4: model 3+HbA1c, hypertension, total cholesterol, triglycerides, HDL-cholesterol.</p><p>Abbreviations: non-DM, IR-, non-diabetic subjects with HOMA-IR <2.5; non-DM, IR+, non-diabetic subjects with HOMA-IR ≥2.5; Q1∼Q4, month-matched 25(OH)D quartiles 1∼4.</p

Characteristics of study subjects according to the presence or absence of diabetes.

<p>Data are expressed as means ± S.D.</p>*<p>Data are expressed as median (1^st quartile, 3^rd quartile). <i>P</i> values are from the t-test using logarithmic transformed values due to skewed distribution.</p>†<p>Regular: ≥3 times/week, ≥30 minutes per session; light: <3 times/week.</p><p>Abbreviations: HOMA-IR, homeostasis model assessment of insulin resistance; NAFLD, non-alcoholic fatty liver disease; LAI, liver attenuation index; 25(OH)D, serum 25-hydroxyvitamin D.</p