Obesity, metabolic dysfunction, and risk of kidney stone disease: a national cross-sectional study

Figures & data

Figure 1. Flowchart identifying process of NHANES 2007 -2018 participant inclusion and exclusion. A total of 34679 participants were surveyed regarding history of kidney stone. Of these subjects, 21090 were excluded due to missing data on MetS-BMI components or other covariates.

In this figure, the flow chart of data cleansing is displayed. First, 34,679 participants were recruited. Then, a total of 21,090 subjects due to missing values of MetS-BMI components were excluded. Finally, 13,589 participants were included into final analysis.

Table 1. Characteristics of the participants.

Clinical characteristics	Metabolic healthy (N = 7232)			Metabolic unhealthy (N = 6357)			P values
	MHN (N = 2382)	MHOW (N = 2376)	MHO (N = 2474)	MUN (N = 401)	MUOW (N = 1328)	MUO (N = 4628)
Age	43.7 (18.1)	46.5 (16.6)	42.3 (15.1)	65.4 (12.7)	63.3 (13.8)	57.4 (14.7)	<0.001
Gender
Female	1284 (53.9%)	1014 (42.7%)	1455 (58.8%)	195 (48.6%)	607 (45.7%)	2219 (47.9%)	<0.001
Male	1098 (46.1%)	1362 (57.3%)	1019 (41.2%)	206 (51.4%)	721 (54.3%)	2409 (52.1%)
Educational levels
Less educated than college	1605 (67.4%)	1702 (71.7%)	1940 (78.4%)	317 (79.4%)	1037 (78.2%)	3848 (83.2%)	<0.001
College degree and above	776 (32.6%)	673 (28.3%)	534 (21.6%)	82 (20.6%)	289 (21.8%)	776 (16.8%)
Race
Mexican American	233 (9.8%)	387 (16.3%)	498 (20.1%)	34 (8.5%)	181 (13.6%)	800 (17.3%)	<.001
Other Hispanic	220 (9.2%)	289 (12.2%)	281 (11.4%)	29 (7.2%)	163 (12.3%)	507 (11.0%)
Non-Hispanic White	1066 (44.8%)	968 (40.7%)	885 (35.8%)	166 (41.4%)	603 (45.4%)	2006 (43.3%)
Non-Hispanic Black	388 (16.3%)	437 (18.4%)	646 (26.1%)	79 (19.7%)	178 (13.4%)	1040 (22.5%)
Other races	475 (19.9%)	295 (12.4%)	164 (6.6%)	93 (23.2%)	203 (15.3%)	275 (5.9%)
Marital status
Not married/divorced  /separated/widowed	1064 (44.7%)	892 (37.5%)	998 (40.4%)	169 (42.1%)	489 (36.9%)	1779 (38.5%)	<0.001
Married/living together	1318 (55.3%)	1484 (62.5%)	1475 (59.6%)	232 (57.9%)	838 (63.1%)	2846 (61.5%)
Alcohol consumption
No	581 (24.7%)	504 (21.6%)	651 (26.7%)	137 (34.9%)	407 (31.3%)	1435 (31.5%)	<0.001
Yes	1769 (75.3%)	1831 (78.4%)	1790 (73.3%)	256 (65.1%)	892 (68.7%)	3116 (68.5%)
Family poverty ratio
<1.3	653 (29.9%)	637 (29.3%)	740 (32.9%)	124 (33.8%)	365 (30.2%)	1415 (33.5%)	<.001
1.3–3.5	765 (35.0%)	792 (36.4%)	896 (39.8%)	161 (43.9%)	486 (40.2%)	1638 (38.8%)
>3.5	768 (35.1%)	746 (34.3%)	613 (27.3%)	82 (22.3%)	359 (29.7%)	1168 (27.7%)
Depression
No	1318 (55.3%)	1368 (57.6%)	1186 (47.9%)	218 (54.4%)	743 (55.9%)	2228 (48.1%)	<0.001
Yes	1064 (44.7%)	1008 (42.4%)	1288 (52.1%)	183 (45.6%)	585 (44.1%)	2400 (51.9%)
Reduced sleep duration
No	2091 (87.8%)	2105 (88.6%)	2103 (85.0%)	352 (87.8%)	1158 (87.2%)	3898 (84.2%)	<0.001
Yes	291 (12.2%)	271 (11.4%)	371 (15.0%)	49 (12.2%)	170 (12.8%)	730 (15.8%)
Glucose (mg/dL)	97.2 (19.6)	100.4 (24.2)	99.8 (21.3)	126.3 (53.1)	122.5 (44.0)	126.6 (46.0)	<0.001
HDL (mg/dL)	62.8 (17.1)	56.8 (15.1)	53.6 (12.6)	54.3 (18.6)	50.5 (16.3)	46.6 (13.7)	<0.001
Triglycerides (mg/dL)	85.3 (47.8)	102.6 (65.6)	99.2 (49.0)	147.8 (95.7)	167.1 (135.2)	170.1 (159.5)	<0.001
Systolic pressure (mmHg)	117.2 (17.6)	118.8 (16.7)	118.1 (14.3)	136.6 (21.5)	133.4 (19.6)	130.6 (18.5)	<0.001
Diastolic pressure (mmHg)	67.1 (11.8)	68.6 (12.2)	69.1 (11.7)	69.1 (14.2)	68.7 (15.5)	70.9 (14.8)	<0.001
Hypertension
No	1806 (75.8%)	1760 (74.1%)	1957 (79.1%)	41 (10.2%)	226 (17.0%)	928 (20.1%)	<0.001
Yes	576 (24.2%)	616 (25.9%)	517 (20.9%)	360 (89.8%)	1102 (83.0%)	3700 (79.9%)
Waist circumference (cm)	81.1 (6.6)	91.8 (6.4)	106.7 (12.2)	88.2 (6.5)	97.3 (6.3)	114.5 (13.0)	<0.001
BMI (Kg/m^2)	21.8 (1.5)	26.0 (1.1)	33.3 (5.3)	22.5 (1.3)	26.3 (1.1)	34.9 (5.9)	<0.001
Kidney stones
No	2223 (93.3%)	2213 (93.1%)	2253 (91.1%)	364 (90.8%)	1149 (86.5%)	3984 (86.1%)	<0.001
Yes	159 (6.7%)	163 (6.9%)	221 (8.9%)	37 (9.2%)	179 (13.5%)	644 (13.9%)

MHN: metabolically healthy normal weight; MHOW: metabolically healthy overweight; MHO: metabolically healthy obesity; MUN: metabolically unhealthy normal weight; MUOW: metabolically unhealthy overweight; MUO: metabolically unhealthy obesity; BMI: body mass index; HDL-C: high-density lipoprotein cholesterol; TC: triglyceride. Data are presented as mean (SD) for continuous measures, and n (%) for categorical measures.

Table 2. Prevalence of kidney stones classified by MetS-BMI phenotypes.

	Metabolic healthy (N = 6344)			Metabolic unhealthy (N = 7236)
Characteristics	MHN	MHOW	MHO	MUN	MUOW	MUO
Number of participants	2382	2376	2474	401	1328	4628
Kidney stone cases	159	163	221	37	179	644
Incidence rate (95% CI)	6.68 (5.74–7.75)	6.86 (5.91–7.95)	8.93 (7.87–10.12)	9.23 (6.75–12.49)	13.48 (11.74–15.43)	13.92 (12.95–14.94)

MHN: metabolically healthy normal weight; MHOW: metabolically healthy overweight; MHO: metabolically healthy obesity; MUN: metabolically unhealthy normal weight; MUOW: metabolically unhealthy overweight; MUO: metabolically unhealthy obesity

P for trend = 0.002 for metabolic healthy subjects.

P for trend = 0.005 for metabolic unhealthy subjects.

Table 3. Association between the phenotypes of MetS-BMI and the prevalence of kidney stones.

MetS–BMI phenotypes	Model 1	Model 2	Model 3	Model 4
MHN	1	1	1	1
MHOW	1.02 (0.78–1.34)	0.97 (0.74–1.28)	0.98 (0.74–1.31)	0.98 (0.73–1.31)
MHO	1.41 (1.13–1.76)**	1.48 (1.18–1.85)**	1.41 (1.11–1.79)**	1.38 (1.09–1.76)**
MUN	1.64 (1.18–2.27)**	1.09 (0.78–1.53)	1.00 (0.69–1.43)	0.98 (0.68–1.41)
MUOW	2.15 (1.69–2.74)***	1.48 (1.15–1.91)**	1.41 (1.08–1.85)*	1.39 (1.06–1.83)*
MUO	2.43 (2.00–2.95)***	1.87 (1.53–2.29)***	1.83 (1.48–2.27)***	1.80 (1.45–2.23)***

MHN: metabolically healthy normal weight; MHOW: metabolically healthy overweight; MHO: metabolically healthy obesity; MUN: metabolically unhealthy normal weight; MUOW: metabolically unhealthy overweight; MUO: metabolically unhealthy obesity.

*: p <0 .05; **: p <0 .01; ***: p < 0.001.

Model 1 was the crude model. Model 2 was adjusted for age, gender and race. Model 3 was further adjusted for education, marital status and family poverty ratio. Model 4 was further adjusted for alcohol consumption, depression status, and sleep duration.