The authors have declared that no competing interests exist.
Obesity and chronic kidney disease (CKD) are major global health problems. There are very little data concerning the prevalence and its associated factors of obesity in non-dialyzed patients who have different stages of CKD. Therefore, in this study, we examined the prevalence of obesity and its associated factors according to the stages of CKD. We used nationwide representative data from the Korean National Health and Nutrition Examination Survey, which was conducted over a 7-year period from 2008 to 2014 by the Korea Centers for Disease Control and Prevention. The results indicated that: (1) general obesity and abdominal obesity were more prevalent in patients with CKD compared to those without CKD; (2) the prevalence of general obesity and abdominal obesity was highest in stage 2 CKD; (3) stages 3a and 3b were the factors associated with general obesity, and stage 3a was significantly associated with abdominal obesity; (4) the association between general obesity/abdominal obesity and CKD disappeared in people with advanced stage 4/5 CKD; and (5) the presence of comorbidities contributed to the development of both general obesity and abdominal obesity. The findings of this study might support the idea that weight loss is a good potential intervention for the prevention of disease progression in moderate CKD (stage 3), but not severe CKD (stage 4/5).
Obesity is a worldwide health threat. Socio-economic burden and the prevalence of obesity worldwide has increased substantially over the last 3 decades [
The present study is a secondary data analysis of the Korean National Health and Nutrition Examination Survey (KNHANES) which was performed over a 7-year period from 2008 to 2014 by the Korea Centers for Disease Control and Prevention (KCDC). The KNHANES is an ongoing, nationwide, population-based, cross-sectional, multistage, stratified, and clustered probability sampling survey with the aim of minimizing sampling bias and ensuring that the sample represents the South Korean population [
In the present study, we included adults aged ≥ 19 years and excluded: (1) those who were pregnant or lactating, (2) those who had missing data for body mass index (BMI) or waist circumference (WC), and (3) those who had missing data for estimated glomerular filtration rate (eGFR). A total of 58,307 individuals were screened, and 37,002 people were included in the study according to the inclusion and exclusion criteria.
General obesity was defined as BMI ≥ 25 kg/m2 based on the cut-off value for Asians [
The KNHANES survey is reviewed and approved by the Institutional Review Board of the Korea Centers for Disease Control and Prevention on an annual basis (Approval numbers: 2008-04EXP-01-C, 2009-01CON-03-2C, 2010-02CON-21-C, 2011-02CON-06-C, 2012-01EXP-01-2C, 2013-07CON-03-4C, 2013-12EXP-03-5C). Each study participant provided written informed consent before the survey. Data were downloaded from the official website of the KNHANES (
Body mass index (BMI) was calculated as weight in kg divided by height in m2. General obesity was defined as BMI ≥ 25 kg/m2 based on the cut-off value for Asians [
Serum creatinine level was measured using the kinetic Jaffe method with an ADVIA 1650 Analyzer (Siemens, Tarrytown, NY, USA) and/or a Hitachi Automatic Analyzer 7600 (Hitachi, Tokyo, Japan) in 2008–2012 and the rate-blanked and compensated Jaffe method with a COBAS 8000 C70 (Roche, Mannheim, Germany) in 2013–2014. Blood samples were obtained after an overnight fast [
The eGFR was calculated using the Modification of Diet in Renal Disease Study equation [
Sociodemographic characteristics of the participants included age, sex, educational level, residential area, household income quartiles and employment status. Health behaviors included alcohol drinking and smoking habits, and mental health included perceived health status assessed by self-reported questionnaires.
Alcohol drinking was defined as the consumption of more than seven glasses of alcoholic drinks per occasion, more than two times per week. Current smoking was defined as both currently smoking and having smoked ≥ 100 cigarettes in a participant’s lifetime. Regular exercise was defined as exercising at a moderate level of intensity (≥ 30 min per session) more than five times per week or a rigorous level of intensity (≥ 20 min per session) more than three times per week. Perceived health status was defined as the level of overall health (i.e., very good/good, fair, or poor/very poor) perceived by the person. Health-related quality of life (HRQoL) was measured using the EuroQoL, which uses both a health-status descriptive system (EQ-5D) and a visual analogue scale (EQ-VAS) ranging from 0 to 100: 0 signifies the worst HRQoL while 100 indicates the best HRQoL [
Data were analyzed using SAS version 9.4 (SAS Institute, Inc., Cary, NC, USA). A p-value < 0.05 was considered statistically significant. All data are presented as means ± standard error (SE) for continuous variables or as proportions (±SE) for categorical variables. Analysis of variance and chi-square tests were performed to evaluate the differences in continuous and categorical variables between the groups. The prevalence of general obesity and abdominal obesity according to eGFR was analyzed as a proportion (±SE). Sociodemographic and clinical characteristics, including mental health and comorbidities, were also examined according to eGFR.
Hierarchical multiple logistic regression analyses were conducted to explore the associations between general obesity, eGFR and all outcomes of interest. The same approach was followed to explore the associations between abdominal obesity, eGFR, and these outcomes. In the analyses, Model 1 was unadjusted, and Model 2 was adjusted for the variables in Model 1 and sociodemographic factors (age, sex, education, employment status). Model 3 was adjusted for the variables in Model 2 and health-related characteristics (sleep duration, smoking, alcohol drinking), and Model 4 was adjusted for the variables in Model 3 and comorbidities (cancer, ischemic heart disease, chronic obstructive pulmonary disease). Finally, Model 5 was adjusted for the variables in Model 4, SBP, DBP, and laboratory measurements (fasting blood glucose, total cholesterol, hemoglobin). The EuroQoL (VAS) was assessed only in 2010–2012, and ferritin was measured only in 2008–2012. Therefore, these factors were omitted from the adjustments. The results were reported using adjusted odd ratios (ORs) and their 95% confidence intervals (CIs). A 95% CI that did not span 1.0 was considered statistically significant.
The prevalence rates of general obesity and abdominal obesity in the study participants were 32.5% and 24%, respectively (
Total | Non-CKD | Stage1 | Stage2 | Stage3a | Stage3b | Stage4/5 | P | |
---|---|---|---|---|---|---|---|---|
Obesity | 32.5% | 32.0% | 37.7% | 53.8% | 43.6% | 45.5% | 37.8% | < .001 |
Abdominal obesity | 24.0% | 23.4% | 29.7% | 45.2% | 40.6% | 40.2% | 30.7% | < .001 |
P-values by Chi-square test
Characteristics | Total |
Non-CKD |
CKD |
CKD |
CKD |
CKD |
CKD |
|
---|---|---|---|---|---|---|---|---|
Age | 45.1±0.15 | 44.4±0.2 | 40.6±1.5 | 54.4±1.1 | 66.9±0.5 | 69.1±1.0 | 59.5±2.4 | < .001 |
≤39 | 39.5 (0.5) | 40.7(0.5) | 50.3(5.7) | 19.2(3.4) | 1.3(0.45) | 0.7(0.7) | 11.8(5.7) | < .001 |
40–49 | 22.6(0.4) | 23.1(0.4) | 23.3(5.2) | 18.7(3.4) | 6.4(1.1) | 5.9(2.2) | 9.6(4.6) | |
50–59 | 18.9(0.3) | 18.8(0.3) | 15.3(4.5) | 24.8(3.4) | 19.9(1.5) | 16.1(3.7) | 25.5(6.0) | |
60–69 | 10.9(0.2) | 10.4(0.2) | 7.3(2.3) | 19.3(2.7) | 23.5(1.4) | 23.0(3.5) | 19.6(5.8) | |
≥70 | 8.2(0.20) | 6.9(0.18) | 3.8(1.6) | 18.1(2.8) | 48.9(1.8) | 54.4(4.2) | 33.4(6.2) | |
Sex | .009 | |||||||
Male | 54.7(0.28) | 54.6(0.29) | 61.0(5.5) | 68.4(3.5) | 54.1(1.7) | 55.1(4.2) | 53.0(7.1) | |
Female | 45.3(0.28) | 45.4(0.29) | 39.0(5.5) | 31.6(3.5) | 45.9(1.7) | 44.9(4.2) | 47.0(7.1) | |
Education | < .001 | |||||||
Elementary to Middle school | 27.6(0.4) | 26.5(0.4) | 24.4(4.9) | 42.0(3.9) | 61.6(1.8) | 70.9(4.0) | 49.8(7.6) | |
High school to University | 72.4(0.4) | 73.5(0.4) | 75.6(4.9) | 58.0(3.9) | 38.4(1.8) | 29.1(4.0) | 50.2(7.6) | |
Residential area, rural | 18.8(1.0) | 18.6(1.0) | 15.4(3.8) | 20.6(3.7) | 24.8(1.9) | 23.3(3.4) | 17.4(5.2) | .001 |
Living without spouse | 28.6(0.4) | 28.6(0.5) | 32.5(5.6) | 18.7(3.4) | 28.0(1.6) | 38.6(4.0) | 35.1(6.6) | .011 |
Household income | .288 | |||||||
Lower to Lower middle | 50.5(0.6) | 50.5(0.6) | 53.8(5.7) | 54.6(4.1) | 46.9(1.9) | 55.7(4.2) | 52.4(7.1) | |
Middle upper to Upper | 49.5(0.6) | 49.5(0.6) | 46.2(5.7) | 45.4(4.1) | 53.1(1.9) | 44.3(4.2) | 47.6(7.1) | |
Currently Unemployed | 34.3%(0.37) | 33.4(0.4) | 42.7(6.0) | 45.7(3.9) | 59.0(1.8) | 75.2(3.7) | 75.9(6.4) | < .001 |
Characteristics | Total |
Non-CKD |
CKD Stage 1 |
CKD Stage 2 |
CKD Stage 3a |
CKD Stage 3b |
CKD Stage 4/5 |
|
---|---|---|---|---|---|---|---|---|
Sleep duration (hr.) | 6.8±0.01 | 6.8±0.01 | 7.1±0.2 | 7.0±0.1 | 6.7±0.1 | 6.5±0.1 | 7.2±0.3 | .020 |
Current smoking | 27.7(0.3) | 27.9(0.3) | 34.0(5.7) | 30.7(3.8) | 15.6(1.3) | 20.8(3.6) | 19.7(5.5) | < .001 |
Alcohol drinking | 60.9(0.4) | 61.5(0.4) | 69.0(5.5) | 60.6(3.9) | 38.8(1.7) | 36.9(4.2) | 37.3(7.4) | < .001 |
Regular exercise | 10.7(0.3) | 10.8(0.3) | 9.2(3.4) | 7.4(1.9) | 8.3(1.0) | 10.3(2.6) | 7.4(3.5) | .190 |
Perceived health status | < .001 | |||||||
Very good/ |
37.1(0.4) | 37.5(0.4) | 26.0(5.1) | 32.8(3.9) | 27.7(1.7) | 20.4(3.4) | 11.1(4.5) | |
Fair | 45.3(0.4) | 45.6(0.4) | 46.4(5.9) | 38.8(3.9) | 38.4(1.7) | 30.2(4.0) | 17.5(5.1) | |
Poor/ |
17.6(0.3) | 16.9(0.3) | 27.6(4.8) | 28.4(3.6) | 34.0(1.7) | 49.4(4.4) | 71.3(6.33) | |
EQ-5D | 0.95±0.0 | 0.95±0.0 | 0.94±0.01 | 0.92±0.01 | 0.88±0.01 | 0.82±0.02 | 0.81±0.03 | < .001 |
EuroQoL: VAS | 74.6±0.2 | 74.8±0.2 | 72.5±2.3 | 71.4±1.6 | 69.7±0.8 | 62.1±2.3 | 61.6±2.4 | < .001 |
Depressive symptom (Yes) | 13.0(0.2) | 12.9(0.2) | 18.3(4.8) | 17.1(3.1) | 14.3(1.3) | 22.1(3.7) | 18.5(5.8) | .012 |
Perceived psychological stress | 27.3(0.3) | 27.5(0.3) | 26.7(5.1) | 28.8(3.7) | 20.5(1.4) | 18.9(3.2) | 20.7(6.0) | .001 |
Suicidal ideation | 13.2(0.3) | 12.9(0.3) | 9.5(3.5) | 14.1(2.8) | 19.4(1.5) | 26.1(3.9) | 34.6(7.5) | < .001 |
Cancer | 2.4(0.1) | 2.3(0.1) | - | 4.0(1.5) | 5.2(0.7) | 4.6(1.6) | 1.9(1.5) | Not estim-able |
Ischemic heart disease | 1.7(0.1) | 1.4(0.1) | 4.0(2.5) | 4.7(1.6) | 7.9(0.9) | 14.0(3.0) | 8.3(3.2) | < .001 |
Stroke | 1.3(0.1) | 1.1(0.1) | 0.8(0.8) | 5.3(1.6) | 7.0(0.8) | 11.0(2.8) | 10.6(4.2) | < .001 |
Hypertension | 24.4(0.3) | 22.8(0.3) | 37.2(5.8) | 61.6(3.9) | 67.0(1.7) | 76.3(3.6) | 87.9(3.6) | < .001 |
DM | 8.7(0.2) | 7.7(0.2) | 33.2(5.6) | 36.0(4.0) | 30.1(1.7) | 45.8(4.3) | 54.8(7.8) | < .001 |
Anemia | 7.1(0.2) | 6.5(0.2) | 6.7(2.6) | 10.3(2.2) | 18.0(1.2) | 40.7(4.2) | 86.8(4.6) | < .001 |
COPD or Asthma | 3.1(0.1) | 3.0(0.1) | 1.0(0.8) | 3.9(1.3) | 5.9(0.8) | 4.9(1.5) | 4.0(2.5) | < .001 |
SBP (mmHg) | 116.8±0.1 | 116.4±0.1 | 122.1±2.0 | 131.8±1.7 | 126.9±0.7 | 128.0±2.0 | 134.1±3.1 | < .001 |
DBP (mmHg) | 75.7±0.1 | 75.7±0.1 | 81.1±1.3 | 82.7±1.1 | 75.5±0.4 | 73.4±1.1 | 76.5±2.2 | < .001 |
BMI (kg/ m2) | 23.7±0.0 | 23.7±0.0 | 23.7±0.5 | 25.3±0.3 | 24.6±0.1 | 24.6±0.3 | 23.5±0.5 | < .001 |
WC (cm) | 81.3±0.1 | 81.1±0.1 | 81.8±1.3 | 87.3±0.9 | 85.5±0.3 | 85.9±0.8 | 82.9±1.5 | < .001 |
Cr (mg/dL) | 0.9±0.0 | 0.8±0.0 | 0.8±0.0 | 1.0±0.0 | 1.2±0.0 | 1.6±0.02 | 3.5±0.3 | < .001 |
Total-C (mg/dL) | 187.4±0.3 | 187.3±0.3 | 199.7±4.7 | 204.8±3.7 | 189.0±1.3 | 181.2±3.9 | 177.0±5.1 | < .001 |
LDL-C | 113.3±0.5 | 113.5±0.5 | 97.8±7.3 | 123.7±6.6 | 110.6±2.5 | 98.5±7.2 | 92.8±7.2 | .001 |
HDL-C | 49.4±0.1 | 52.2±0.1 | 53.5±1.5 | 46.4±0.8 | 46.6±0.4 | 44.9±1.2 | 45.3±1.9 | < .001 |
Triglycerides | 137.6±0.8 | 136.2±0.8 | 211.9±30.5 | 203.2±12.1 | 160.4±3.4 | 165.2±9.4 | 148.2±9.4 | < .001 |
Fe (umol/dL) | 117.5±0.6 | 118.0±0.6 | 114.2±9.4 | 124.4±7.3 | 101.5±1.8 | 91.30±5.6 | 73.36±5.1 | < .001 |
Ferritin (ng/mL) | 90.9±0.9 | 90.3±0.9 | 127.9±20.2 | 138.0±16.0 | 93.0±3.0 | 111.0±8.9 | 142.7±26.4 | < .001 |
Hb (g/dL) | 14.3±0.0 | 14.3±0.0 | 14.7±0.2 | 14.7±0.1 | 13.7±0.1 | 12.8±0.1 | 11.2±0.2 | < .001 |
FBS (mg/dL) | 97.6±0.2 | 97.1±0.1 | 120.9±5.7 | 123.7±3.2 | 108.2±1.0 | 111.2±3.3 | 114.6±6.3 | < .001 |
Model 1 | Model 2 | Model 3 | Model 4 | Model 5 | ||||||
---|---|---|---|---|---|---|---|---|---|---|
OR | 95% CI | OR | 95% CI | OR | 95% CI | OR | 95% CI | OR | 95% CI | |
Non-CKD | Reference | Reference | Reference | Reference | Reference | |||||
CKD Stage 1 | 1.29 | (0.80 to 2.07) | 1.24 | (0.73 to 2.09) | 1.48 | (0.85 to 2.61) | 1.02 | (0.55 to 1.90) | 0.70 | (0.34to 1.43) |
CKD Stage 2 | 2.47 | (1.79 to 3.40) | 2.14 | (1.53 to 2.99) | 2.12 | (1.50 to 3.00) | 1.63 | (1.14 to 2.34) | 0.99 | (0.66 to 1.47) |
CKD Stage 3a | 1.64 | (1.43 to 1.90) | 1.48 | (1.28 to 1.71) | 1.45 | (1.24 to 1.69) | 1.21 | (1.02 to 1.42) | 1.30 | (1.09 to 1.55) |
CKD Stage 3b | 1.77 | (1.28 to 2.45) | 1.66 | (1.17 to 2.36) | 1.76 | (1.21 to 2.55) | 1.60 | (1.07 to 2.38) | 1.91 | (1.24 to 2.94) |
CKD Stage 4/5 | 1.29 | (0.71 to 2.35) | 1.32 | (0.69 to 2.52) | 1.57 | (0.79 to 3.14) | 1.01 | (0.47 to 2.15) | 1.05 | (0.43 to 2.55) |
Age, per 10-y older | 1.04 | (1.01 to 1.06) | 1.02 | (0.99 to 1.04) | 0.89 | (0.87 to 0.92) | 0.84 | (0.81 to 0.87) | ||
Male, sex | 1.50 | (1.42 to 1.59) | 1.48 | (1.38 to 1.60) | 1.33 | (1.23 to 1.43) | 0.68 | (0.62 to 0.76) | ||
Elementary to middle school | 1.26 | (1.17 to 1.36) | 1.21 | (1.12 to 1.32) | 1.16 | (1.06 to 1.26) | 1.13 | (1.03 to 1.24) | ||
Residential area, rural | 1.05 | (0.97 to 1.13) | 1.04 | (0.95 to 1.13) | 1.07 | (0.98 to 1.16) | 1.07 | (0.98 to 1.17) | ||
Living without spouse | 0.81 | (0.75 to 0.87) | 0.79 | (0.73 to 0.85) | 0.74 | (0.69 to 0.80) | 0.82 | (0.76 to 0.89) | ||
Currently Unemployed | 0.86 | (0.81 to 0.92) | 0.82 | (0.77 to 0.88) | 0.81 | (0.76 to 0.87) | 0.84 | (0.78 to 0.91) | ||
Sleep Duration (hr.) | 0.97 | (0.94 to 0.99) | 0.96 | (0.94 to 0.99) | 0.95 | (0.93 to 0.97) | ||||
Current smoking | 1.00 | (0.92 to 1.08) | 1.02 | (0.94 to 1.10) | 0.88 | (0.81 to 0.96) | ||||
Alcohol drinking | 0.98 | (0.92 to 1.05) | 0.92 | (0.86 to 0.98) | 1.05 | (0.98 to 1.13) | ||||
Perceived health status | ||||||||||
Very good/Good | Reference | Reference | Reference | |||||||
Fair | 1.13 | (1.06 to 1.20) | 1.07 | (1.00 to 1.14) | 1.00 | (0.93 to1.08) | ||||
Poor/Very poor | 1.19 | (1.08 to 1.31) | 1.04 | (0.94 to 1.15) | 1.01 | (0.91 to 1.12) | ||||
EQ-5D | 0.45 | (0.33 to 0.60) | 0.40 | (0.30 to 0.55) | 0.40 | (0.29 to 0.55) | ||||
Depressive Symptom (Yes) | 0.92 | (0.84 to 1.02) | 0.94 | (0.85 to 1.04) | 0.94 | (0.84 to 1.05) | ||||
Perceived psychological stress | 1.15 | (1.07 to 1.24) | 1.13 | (1.05 to 1.22) | 1.11 | (1.02 to 1.20) | ||||
Suicidal ideation | 0.90 | (0.82 to 0.99) | 0.90 | (0.81 to 0.99) | 0.89 | (0.80 to 0.99) | ||||
Cancer | 0.85 | (0.70 to 1.03) | 0.90 | (0.74 to 1.10) | ||||||
Ischemic heart disease | 1.00 | (0.81 to 1.24) | 1.34 | (1.08 to 1.65) | ||||||
Stroke | 0.94 | (0.76 to 1.17) | 1.11 | (0.89 to 1.39) | ||||||
Hypertension | 2.59 | (2.40 to 2.79) | 1.66 | (1.51 to 1.83) | ||||||
Diabetes mellitus | 1.61 | (1.46 to 1.78) | 1.08 | (0.93 to 1.25) | ||||||
Anemia | 0.63 | (0.56 to 0.71) | 1.15 | (1.00 to 1.34) | ||||||
COPD or Asthma | 0.98 | (0.82 to 1.17) | 1.09 | (0.90 to 1.32) | ||||||
SBP, per 10 mmHg | 1.05 | (1.02 to 1.09) | ||||||||
DBP, per 10 mmHg | 1.27 | (1.21 to 1.34) | ||||||||
Total cholesterol, per 10 mg/dL | 1.10 | (1.08 to 1.11) | ||||||||
HDL-C, per 10 mg/dL | 0.63 | (0.61 to 0.65) | ||||||||
Triglycerides, per 10 mg/dL | 1.00 | (1.00 to 1.01) | ||||||||
Hemoglobin per 1g/dL | 1.17 | (1.13 to 1.22) | ||||||||
Fasting blood sugar, per 10 mg/dL | 1.08 | (1.06 to 1.11) |
Model 1 | Model 2 | Model 3 | Model 4 | Model 5 | ||||||
---|---|---|---|---|---|---|---|---|---|---|
OR | 95% CI | OR | 95% CI | OR | 95% CI | OR | 95% CI | OR | 95% CI | |
Non-CKD | Reference | Reference | Reference | Reference | Reference | |||||
CKD Stage 1 | 1.39 | (0.86 to 2.24) | 1.29 | (0.76to 2.18) | 1.25 | (0.71 to 2.18) | 0.78 | (0.44 to 1.41) | 0.52 | (0.27 to 0.99) |
CKD Stage 2 | 2.71 | (1.97 to 3.72) | 2.21 | (1.59 to 3.08) | 2.16 | (1.52 to 3.07) | 1.66 | (1.14 to 2.41) | 1.06 | (0.73 to 1.55) |
CKD Stage 3a | 2.24 | (1.95 to 2.57) | 1.36 | (1.17 to 1.58) | 1.40 | (1.19 to 1.65) | 1.18 | (0.98 to 1.40) | 1.23 | (1.02 to 1.49) |
CKD Stage 3b | 2.20 | (1.58 to 3.08) | 1.21 | (0.84 to 1.72) | 1.17 | (0.79 to 1.72) | 1.07 | (0.69 to 1.65) | 1.22 | (0.75 to 1.96) |
CKD Stage 4/5 | 1.45 | (0.82 to 2.56) | 1.01 | (0.56 to 1.84) | 1.14 | (0.59 to 2.18) | 0.92 | (0.45 to 1.88) | 0.99 | (0.43 to 2.30) |
Age, per 10-y older | 1.21 | (1.17 to 1.24) | 1.20 | (1.17 to 1.24) | 1.07 | (1.03 to 1.11) | 1.03 | (0.99 to 1.07) | ||
Male, sex | 1.22 | (1.15 to 1.30) | 1.15 | (1.06 to 1.24) | 0.99 | (0.91 to 1.08) | 0.51 | (0.46 to 0.57) | ||
Elementary to middle school | 1.36 | (1.26 to 1.48) | 1.28 | (1.17 to 1.40) | 1.19 | (1.09 to 1.31) | 1.16 | (1.05 to 1.28) | ||
Residential area, rural | 1.16 | (1.05 to 1.27) | 1.15 | (1.04 to 1.27) | 1.19 | (1.08 to 1.33) | 1.20 | (1.08 to 1.34) | ||
Living without spouse | 0.92 | (0.86 to 0.99) | 0.90 | (0.83 to 0.97) | 0.86 | (0.79 to 0.93) | 0.92 | (0.84 to 1.01) | ||
Currently Unemployed | 0.99 | (0.93 to 1.06) | 0.95 | (0.88 to 1.03) | 0.94 | (0.87 to 1.02) | 0.98 | (0.91 to 1.07) | ||
Sleep Duration (hr.) | 0.98 | (0.96 to 1.01) | 0.98 | (0.96 to 1.01) | 0.97 | (0.94 to 1.00) | ||||
Current smoking | 1.10 | (1.01 to 1.20) | 1.12 | (1.03 to 1.23) | 0.98 | (0.89 to 1.07) | ||||
Alcohol drinking | 1.06 | (0.98 to 1.13) | 1.00 | (0.93 to 1.08) | 1.15 | (1.07 to 1.25) | ||||
Perceived health status | ||||||||||
Very good/Good | Reference | Reference | Reference | |||||||
Fair | 1.22 | (1.13 to 1.32) | 1.15 | (1.07 to 1.25) | 1.10 | (1.01 to 1.19) | ||||
Poor/Very poor | 1.42 | (1.28 to 1.58) | 1.24 | (1.11 to 1.38) | 1.23 | (1.10 to 1.38) | ||||
EQ-5D | 0.46 | (0.34 to 0.63) | 0.39 | (0.28 to 0.54) | 0.39 | (0.28 to 0.55) | ||||
Depressive Symptom (Yes) | 0.89 | (0.80 to 0.99) | 0.90 | (0.80 to 1.01) | 0.91 | (0.80 to 1.02) | ||||
Perceived psychological stress | 1.18 | (1.09 to 1.28) | 1.17 | (1.07 to 1.27) | 1.14 | (1.05 to 1.25) | ||||
Suicidal ideation | 1.00 | (0.89 to 1.11) | 1.00 | (0.89 to 1.12) | 1.01 | (0.90 to 1.13) | ||||
Cancer | 0.84 | (0.69 to 1.01) | 0.89 | (0.73 to 1.07) | ||||||
Ischemic heart disease | 1.04 | (0.85 to 1.27) | 1.32 | (1.06 to 1.64) | ||||||
Stroke | 0.86 | (0.68 to 1.07) | 0.97 | (0.76 to 1.22) | ||||||
Hypertension | 2.37 | (2.19 to 2.57) | 1.61 | (1.46 to 1.78) | ||||||
Diabetes mellitus | 1.85 | (1.68 to 2.05) | 1.22 | (1.05 to 1.43) | ||||||
Anemia | 0.50 | (0.44 to 0.57) | 0.94 | (0.80 to 1.11) | ||||||
COPD or Asthma | 1.03 | (0.86 to 1.25) | 1.13 | (0.92 to 1.38) | ||||||
SBP, per 10 mmHg | 1.07 | (1.03 to 1.10) | ||||||||
DBP, per 10 mmHg | 1.16 | (1.11 to 1.22) | ||||||||
Total cholesterol, per 10 mg/dL | 1.08 | (1.07 to 1.09) | ||||||||
HDL-C, per 10 mg/dL | 0.65 | (0.63 to 0.68) | ||||||||
Triglycerides, per 10 mg/dL | 1.00 | (1.00 to 1.01) | ||||||||
Hemoglobin (g/dL) | 1.21 | (1.16 to 1.26) | ||||||||
Fasting blood sugar, per 10 mg/dL | 1.08 | (1.06 to 1.11) |
It is thought that obese people are more likely to develop CKD and ESKD because of hemodynamic and histopathological changes in the kidney in the setting of obesity [
The findings of the present study can be summarized as follows: (1) general obesity and abdominal obesity were more prevalent in CKD groups compared to the non-CKD group; (2) the prevalence of general obesity and abdominal obesity was highest in stage 2 CKD; (3) stages 3a/3b CKD were the significant factors associated with general obesity, and stage 3a CKD was significantly associated with abdominal obesity; and (4) the presence of various comorbidities was an independent contributor to the development of both general obesity and abdominal obesity.
Our study showed that people with CKD stages 3a and 3b were more likely to have general obesity and people with CKD stages 3a were more likely to have abdominal obesity. It has been suggested that WC, not BMI, might be a better indicator of obesity-related health risk [
The present study also found a relatively lower prevalence of general obesity and abdominal obesity in CKD stage 4/5 than other CKD stages (
Viewed in combination, these previous findings and those of the current study may suggest that obesity is strongly associated with the development and progression of CKD at an early stage but confer a benefit in advanced CKD. In other words, obesity might be a double-edged sword for CKD patients. Thus, a therapeutic approach to overweight and obesity in patients with advanced CKD should be approached carefully.
Regarding the factors associated with general obesity /abdominal obesity other than CKD (Tables
Of note, we have used the Korean definition in this study to define general and abdominal obesity [
The findings of the present study have a few important clinical implications. First, these findings are congruent with those of previous studies in that they revealed a significant association between general obesity/abdominal obesity and CKD. Second, we further observed that the association between general obesity/abdominal obesity and CKD disappears when CKD reaches an advanced stage (stage 4/5). This means that weight loss might be a sign of poor clinical outcomes in patients with severe CKD. Third, CKD itself could be a contributing factor to obesity in moderate CKD (stage 3). Given the role of obesity in the progression of CKD, patients with moderate CKD can enter a vicious cycle if they have both CKD and obesity. In conclusion, the findings of this study clearly support the idea that weight loss is a good potential intervention for the prevention of progression in moderate CKD (stage 3), but not severe CKD (stage 4/5).
The main strength of this study is that it was done in a large number of individuals using nationwide and representative survey data. Also the ethnic homogeneity of study participants can be another strength since it enabled us to reduce the potential confounding effects of different races and ethnicities to address the relationship between obesity and CKD. However, this ethnic homogeneity of study participant could be viewed as limitation since further studies will be needed in populations with different ethnic backgrounds before generalization of our study findings. Furthermore, as mentioned earlier, the cross-sectional design of the KNHANES precluded the identification of a causal relationship, and this represents another limitation of the present study. Due to the nature of cross-sectional studies, patients with acute kidney injury could have been accidentally included in this study given that a single measurement of eGFR might not represent CKD accurately.
In conclusion, there is increased prevalence of obesity in patients with CKD in South Korea except for severe CKD patients. Stages 3 CKD seems to be an independent factor for obesity as well. The findings of this study clearly support the idea that weight loss might be a good potential intervention for the prevention of disease progression in moderate CKD (stage 3), but not severe CKD (stage 4/5).
We are grateful to the Korea Centers for Disease Control and Prevention for allowing us to use the Korea National Health and Nutrition Examination Survey (KNHANES) data.