Skip to main content

Table 2 Multivariable-adjusted geometric mean concentrations of urinary aMT6s (ng/mg creatinine) at urine collection (1996–1999) by categories of body size and night shift work among 1,343 women in Nurses’ Health Study II a

From: The association of body size in early to mid-life with adult urinary 6-sulfatoxymelatonin levels among night shift health care workers

   

Model 1b

 

Model 2c

 

Variable

Category definition

N

Geometric Mean (95% CI)

P-trend

Geometric Mean (95% CI)

P-trend

Birth weight (pounds)d

<5.5

34

35 (29–43)

 

34 (28–42)

 
 

5.5-6.9

299

43 (40–46)

 

42 (39–45)

 
 

7.0-8.4

632

41 (40–44)

 

42 (40–44)

 
 

8.5-9.9

137

44 (40–49)

 

45 (40–50)

 
 

≥10

19

31 (24–41)

0.88

32 (24–42)

0.46

Somatotype at age 5

1 (leanest)

307

43 (40–46)

 

42 (39–45)

 
 

2

417

41 (39–44)

 

41 (38–43)

 
 

3

354

43 (40–46)

 

43 (41–46)

 
 

4

161

40 (37–44)

 

42 (38–46)

 
 

≥5 (heaviest)

86

41 (36–47)

0.47

44 (38–50)

0.50

Somatotype at age 10

1 (leanest)

254

41 (38–45)

 

40 (37–43)

 
 

2

426

43 (41–46)

 

42 (40–45)

 
 

3

326

42 (39–45)

 

42 (40–45)

 
 

4

193

41 (38–45)

 

42 (39–46)

 
 

≥5 (heaviest)

132

40 (36–45)

0.49

43 (39–48)

0.24

Height (inches)

≤62

236

42 (38–45)

 

42 (39–45)

 
 

63-64

391

43 (40–46)

 

43 (40–46)

 
 

65

193

43 (40–47)

 

43 (39–47)

 
 

66-67

316

40 (37–43)

 

40 (38–43)

 
 

≥68

207

41 (37–44)

0.30

41 (37–44)

0.23

Body mass index at age 18 (kg/m2)

<19

306

45 (42–48)

 

42 (39–46)

 
 

19-19.9

260

41 (38–44)

 

40 (37–43)

 
 

20-22.4

516

43 (41–46)

 

44 (41–46)

 
 

22.5-24.9

160

35 (32–39)

 

38 (34–42)

 
 

25-27.4

59

36 (31–42)

 

41 (34–48)

 
 

≥27.5

32

39 (31–49)

0.001

45 (36–56)

0.86

Weight change since age 18 (kg)

<5

452

45 (43–48)

 

41 (39–44)

 
 

5- < 20

633

42 (40–44)

 

42 (40–44)

 
 

≥20

229

36 (33–39)

<0.0001

43 (38–48)

0.66

Waist circumference (inches)

<26.75

163

45 (41–50)

 

41 (37–46)

 
 

26.75 - < 29

203

49 (45–54)

 

46 (42–51)

 
 

29- < 31

183

41 (37–45)

 

40 (36–44)

 
 

31- < 34.5

182

38 (34–41)

 

40 (36–44)

 
 

≥34.5

117

36 (32–40)

<0.0001

43 (37–50)

0.49

Waist to hip ratio

<0.72

150

46 (41–51)

 

44 (40–49)

 
 

0.72- < 0.75

162

44 (40–49)

 

42 (38–47)

 
 

0.75- < 0.79

220

42 (38–45)

 

41 (38–45)

 
 

0.79- < 0.82

154

38 (35–43)

 

40 (36–44)

 
 

≥0.82

158

40 (36–45)

0.02

43 (39–48)

0.55

Body mass index at urine collection (kg/m2)

<20

137

50 (45–56)

   
 

20-22.4

366

46 (43–49)

   
 

22.5-24.9

340

43 (40–46)

   
 

25-27.4

209

38 (35–42)

   
 

27.5-29.9

105

37 (33–41)

   
 

≥30

162

34 (30–37)

<0.0001

  

Shift work 2 weeks prior to urine collection (nights)

0

1227

42 (41–44)

   
 

1-4

76

40 (35–46)

   
 

>4

37

38 (31–47)

0.29

  

Shift work 2 years prior to urine collection (months)

0

1158

42 (41–44)

   
 

1-9

78

43 (37–49)

   
 

10-19

26

38 (30–49)

   
 

≥20

73

37 (32–43)

0.08

  

Cumulative shift work prior to urine collection (years)e

0

447

43 (40–45)

   
 

1-9

804

41 (40–43)

   
 

≥10

85

42 (36–48)

0.37

  
  1. aaMT6s, 6-sulfatoxymelatonin.
  2. bAnalyses of body size adjusted for age at urine collection (5 year age categories), first-morning urine (yes, no), batch, number of pack-years smoked (0, <10, 10–24, ≥25 pack years), parity (nulliparous, 1–2 children, ≥3 children), physical activity in MET-hours/week (quintiles), and night shift work in 2 weeks prior to urine collection (0, 1–4 , >4 night shifts). Multivariable analyses for shift work adjust for the same factors except they adjust for body mass index (BMI) in kg/m2 at urine collection (<20, 20.0-22.4, 22.5-24.9, 25.0-27.4, 27.5-29.9, ≥30) instead of night shift work in 2 weeks prior to urine collection.
  3. cAnalyses of body size adjust for the same factors as model 1, plus BMI in kg/m2 at urine collection (<20, 20.0-22.4, 22.5-24.9, 25.0-27.4, 27.5-29.9, ≥30).
  4. dAmong women (n = 1,185) who were born full-term.
  5. eCumulative shift work, updating baseline lifetime shift work history through urine collection.
Back to article page

BMC Public Health

ISSN: 1471-2458

Contact us