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Table 2 Characteristics of study sample by tertiles of serum 25(OH)D (n = 1514)a

From: Higher serum 25(OH)D level is associated with decreased risk of impairment of glucose homeostasis: data from Southwest China

 

Tertiles of serum 25(OH)D (ng/ml)

P

 

Tertile 1

12.6 (9.5, 15.1)b

Tertile 2

20.6 (18.6, 23.1)b

Tertile 3

31.9 (27.9, 38.9)b

n (%)

504 (33.3)

505 (33.4)

505 (33.4)

–

Age (yrs)

58.9 (47.0, 64.9)

47.8 (34.9, 57.9)

57.7 (49.5, 62.2)

< 0.0001

Male (n (%))

203 (40.3)

222 (44.0)

141 (27.9)

0.0001

Pre-diabetesc (n (%))

323 (64.1)

334 (66.1)

330 (65.4)

0.847

Blood parameters

 Fasting plasma glucose (mmol/L)

5.51 (5.22, 5.82)

5.51 (5.17,5.84)

5.49 (5.20, 5.90)

0.929

 Fasting insulin (μIU/mL)

7.00 (4.40, 10.86)

6.50 (4.20, 10.40)

5.80 (3.90, 9.35)

0.014

 HbA1c (%)

5.50 (5.20, 5.80)

5.50 (5.20, 5.80)

5.60 (5.30, 5.80)

0.483

 HOMA2-IRd

0.95 (0.59, 1.45)

0.87 (0.56, 1.39)

0.78 (0.52, 1.26)

0.018

 Serum calcium2+ (mmol/L)

2.44 (2.36, 2.52)

2.43 (2.33, 2.51)

2.40 (2.30, 2.50)

0.006

Anthropometric parameters

 Overweighte (n (%))

208 (41.2)

202 (40.1)

219 (43.3)

0.707

 Overweightf (n (%))

146 (29.0)

138 (27.4)

158 (31.3)

0.566

 Body mass index (kg/m2)

22.9 (20.9, 25.3)

23.3 (21.1, 25.2)

23.4 (21.1, 25.6)

0.372

 Waist circumference (cm)

83.5 (77.4, 89.8)

84.1 (77.3, 90.0)

84.7 (78.1, 92.2)

0.119

Social-demographic data

 High education levelg (n (%))

237 (47.0)

243 (48.1)

196 (38.8)

0.042

 High monthly personal incomeh (n (%))

201 (39.9)

197 (39.0)

178 (35.3)

0.0005

 Mental workeri (n (%))

188 (37.3)

196 (38.8)

126 (25.0)

< 0.0001

Lifestyles

 Smoking status (current, n (%))

72 (14.3)

79 (15.6)

66 (13.1)

0.539

 MVPA (MET-hour/week)j

90.0 (54.6, 139.4)

89.24 (58.3, 137.4)

105.90 (66.6, 153.5)

0.019

Total energy intake (kcal/d)

1563.3 (1250.7, 1884.8)

1575.7 (1261.0, 1963.3)

1530.0 (1232.6, 1839.8)

0.361

Seasonk (summer, n (%))

84 (16.7)

138 (27.3)

150 (29.7)

< 0.0001

  1. aValues are median (25th percentile, 75th percentile) for non-normally-distributed continuous variables and n (%) for categorical variables. For non-normally distributed data, Kruskal-Wallis test was used to test the differences of the parameters among the tertiles of 25(OH)D, and for categorical variables, chi-square test were used
  2. bValues are median (25th percentile, 75th percentile) in tertiles of vitamin D (ng/ml)
  3. cPre-diabetes was defined using the updated classification and diagnosis of diabetes of American Diabetes Association (ADA) [3]
  4. dHOMA2-IR, Homeostasis model assessment 2-insulin resistance, calculated by Wallace Formula [21]
  5. eBody mass index ≥24.0 kg/m2 [23]
  6. fBody mass index ≥25.0 kg/m2 [48]
  7. gAt least 12 years of school education
  8. hMonthly personal income at least ≥3200 CNY (Chinese Yuan), which is moderate level among the general population in Southwest China [26]
  9. iMental worker includes professional and technical personnel (teacher/policeman/doctor etc), legislator & administrator, businessman and student [25]
  10. jMVPA: moderate-to-vigorous physical activity (MET-hour/week) [27]. MET: Metabolic equivalent
  11. kSummer in Southwest China is from June to August generally
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BMC Endocrine Disorders

ISSN: 1472-6823

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