Table 1 Baseline characteristics of study participants according to quintiles of serum IGF-1 (nmol l−1): 3311 women 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 numbers

861

813

479

681

477

  

IGF-1, nmol l−1, mean (s.e.)

9.2 (0.06)

13.0 (0.03)

15.5 (0.02)

18.3 (0.04)

25.2 (0.22)

15.2 (0.10)

<0.001

Age, years, mean (s.e.)

68.7 (0.4)

66.2 (0.3)

65.1 (0.4)

64.4 (0.3)

63.2 (0.4)

65.9 (0.2)

<0.001

Anthropometry mean (s.e.)

 Height, cm

158.8 (0.3)

159.9 (0.2)

160.4 (0.3)

160.6 (0.2)

160.9 (0.3)

160.0 (0.1)

<0.001

 BMI, kg/m2

28.7 (0.2)

28.4 (0.2)

27.6 (0.2)

27.7 (0.2)

27.6 (0.2)

28.1 (0.1)

<0.001

Co-morbidities, % (s.e.)

 Diabetes

8.5 (0.9)

6.0 (0.8)

6.9 (1.2)

5.9 (0.9)

7.8 (1.2)

7.0 (0.4)

0.213

 Cancer

6.6 (0.8)

4.5 (0.7)

4.6 (1.0)

3.2 (0.7)

6.1 (1.1)

5.0 (0.4)

0.029

 Cardiovascular disease

26.6 (1.5)

24.4 (1.5)

21.5 (1.9)

18.6 (1.5)

23.9 (2.0)

23.3 (0.7)

0.005

Psychosocial factors, % (s.e.)

 Lowest wealth quintile

23.1 (1.4)

16.0 (1.3)

11.7 (1.5)

15.0 (1.4)

14.5 (1.6)

16.8 (0.7)

<0.001

 No educational qualifications

34.1 (1.6)

30.3 (1.6)

29.0 (2.1)

27.2 (1.7)

23.1 (1.9)

29.4 (0.8)

0.001

 Lives alone

43.1 (1.7)

37.5 (1.7)

28.4 (2.1)

32.8 (1.8)

36.3 (2.2)

36.5 (0.8)

<0.001

Behavioural factors, % (s.e.)

 Sedentary or low physical activity

39.4 (1.7)

30.0 (1.6)

26.5 (2.0)

25.8 (1.7)

30.2 (2.1)

31.1 (0.8)

<0.001

 Current smoking

12.2 (1.1)

13.3 (1.2)

12.7 (1.5)

13.5 (1.3)

16.1 (1.7)

13.4 (0.6)

0.663

 Daily alcohol intake

15.2 (1.2)

16.0 (1.3)

16.5 (1.7)

15.9 (1.4)

16.8 (1.7)

16.0 (0.6)

0.902

Depression

 CES-D score, mean (s.e.)

1.8 (0.07)

1.6 (0.07)

1.3 (0.08)

1.5 (0.07)

1.6 (0.09)

1.6 (0.03)

<0.001

 High depression symptoms, % (s.e.)

20.6 (1.3)

15.9 (1.3)

14.4 (1.6)

14.2 (1.3)

17.8 (1.5)

16.8 (0.7)

0.005

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

7.1 (0.9)

6.4 (0.9)

5.4 (1.0)

6.5 (0.9)

6.7 (1.1)

6.5 (0.4)

0.837

  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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