Table 2 Baseline characteristics of study participants according to quintiles of serum IGF-1 (nmol l−1): 2706 men in the English Longitudinal Study of Ageing, 2008

From: Insulin-like growth factor 1 and risk of depression in older people: the English Longitudinal Study of Ageing

 

IGF-1 quintile (range)

P-value for difference

 

1

2

3

4

5

All

 
 

(2–11 nmol  l−1)

(12–14 nmol l−1)

(15–16 nmol l−1)

(17–20 nmol l−1)

(21–65 nmol l−1)

  

Subject number

483

615

384

667

557

  

IGF-I, nmol l−1 (s.e.)

9.3 (0.08)

13.1 (0.03)

15.5 (0.03)

18.4 (0.04)

25.1 (0.22)

16.5 (0.11)

<0.001

Age, years, mean (s.e.)

68.7 (0.5)

65.3 (0.4)

65.0 (0.5)

64.4 (0.3)

64.0 (0.3)

65.4 (0.2)

<0.001

Anthropometry, mean (s.e.)

 Height, cm

171.7 (0.3)

172.8(0.3)

173.8 (0.4)

173.8 (0.3)

174.2 (0.3)

173.3 (0.1)

<0.001

 BMI, kg/m2

28.6 (0.2)

27.8 (0.2)

27.9 (0.2)

28.0 (0.2)

27.9 (0.2)

28.0 (0.1)

0.078

Co-morbidities, % (s.e.)

 Diabetes

12.6 (1.5)

6.8 (1.0)

6.3 (1.2)

10.6 (1.2)

11.1 (1.3)

9.6 (5.7)

0.001

 Cancer

4.8 (1.0)

5.4 (1.0)

4.4 (1.1)

5.2 (0.9)

4.3 (0.9)

4.9 (4.1)

0.897

 Cardiovascular disease

31.5 (2.1)

24.6 (1.7)

25.7 (2.2)

26.3 (1.7)

27.2 (1.9)

26.9 (0.9)

0.121

Psychosocial factors, % (s.e.)

 Lowest wealth quintile

18.0 (1.8)

13.3 (1.4)

14.3 (1.8)

12.0 (1.3)

13.1 (1.4)

13.9 (0.7)

0.167

 No educational qualifications

25.9 (2.0)

20.0 (1.6)

23.4 (2.1)

17.3 (1.5)

16.3 (1.6)

20.1 (0.8)

0.056

 Lives alone

26.7 (2.0)

20.7 (1.6)

20.8 (2.1)

21.4 (1.6)

16.7 (1.6)

21.1 (0.8)

0.003

Behavioural factors, % (s.e.)

 Sedentary or low physical activity

26.9 (2.0)

18.4 (1.6)

22.1 (2.1)

17.4 (1.5)

21.9 (1.8)

20.9 (0.8)

0.005

 Current smoking

13.7 (1.6)

12.7 (1.3)

12.8 (1.7)

11.8 (1.3)

14.0 (1.5)

12.9 (0.6)

0.306

 Daily alcohol intake

28.6 (2.2)

24.7 (1.7)

27.6 (2.2)

26.4 (1.7)

24.1 (1.8)

26.1 (0.8)

<0.001

Depression

 CES-D8 score, mean (s.e.)

1.0 (0.08)

0.9 (0.06)

0.8 (0.07)

0.9 (0.06)

1.1 (0.07)

0.9 (0.03)

0.07

 High depression symptoms, % (s.e.)

9.3 (1.3)

7.5 (1.1)

5.7 (1.0)

6.7 (1.0)

11.0 (1.3)

8.1 (0.5)

0.018

 Physician-diagnosed depression, % (s.e.)

5.2 (1.0)

4.2 (0.8)

4.2 (1.0)

3.9 (0.7)

6.5 (1.0)

4.8 (0.4)

0.238

  1. Abbreviations: BMI, body mass index; CES-D, Center for Epidemiologic Studies Depressive scale; IGF-1, insulin-like growth factor 1.
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