Table 8 The prevalence (%) of ISH by seven waves

 Male

30.6(29.0–32.1)

24.8(23.6–26.1)

15.3(14.2–16.3)

15.0(13.9–16.1)

26.5(25.2–27.8)

50.1(48.1–52.1)

29.0(26.9–31.0)

 Female

30.5(29.2–31.7)

25.2(24.1–26.3)

13.7(12.9–14.6)

13.8(13.0–14.7)

28.2(27.1–29.3)

23.5(21.9–25.2)

31.9(30.1–33.6)

 p

0.930

0.669

0.025

0.100

0.054

< 0.001

0.036

 80–89 yrs

31.3(29.7–32.8)

25.1(23.9–26.3)

15.1(14.0–16.1)

15.6(14.4–16.7)

30.4(29.0–31.8)

26.2(24.5–27.9)

30.8(28.832.7)

 90–99 yrs

30.1(28.5–31.8)

25.6(24.2–27.0)

14.2(13.1–15.3)

14.8(13.7–15.9)

24.0(26.0–28.7)

27.1(25.4–28.9)

30.5(28.2–32.7)

 100- yrs

30.0(28.1–31.8)

24.1(22.3–25.8)

13.5(12.3–14.7)

11.7(10.5–12.9)

23.4(22.4–25.5)

23.3(21.0–25.5)

30.7(27.6–33.9)

 p _{for trend}

0.269

0.491

0.043

< 0.001

< 0.001

0.098

0.941

 City

29.1(27.9–30.3)

22.8(21.4–24.3)

13.5(12.7–14.4)

11.6(10.3–13.0)

23.0(21.3–24.7)

22.4(19.9–24.9)

26.9(23.4–30.4)

 Town

25.0(23.5–26.4)

14.2(12.9–15.6)

14.6(13.7–15.5)

26.2(24.4–28.1)

24.2(22.3–26.1)

31.4(29.6–33.2)

 Rural

33.0(31.4–34.6)

26.9(25.6–28.3)

16.2(14.8–17.6)

15.8(14.4–17.2)

29.5(28.4–30.6)

28.0(26.5–29.5)

30.9(28.5–33.3)

 p _{for trend}

< 0.001

< 0.001

0.005

< 0.001

< 0.001

< 0.001

0.084

 East

32.4(31.3–33.8)

27.1(25.9–28.2)

16.1(14.7–17.5)

21.1(19.5–22.6)

31.0(29.9–32.1)

31.7(30.1–33.2)

32.4(30.5–34.2)

 Central

30.3(27.9–32.8)

19.4(17.9–20.9)

14.9(14.0–15.8)

14.1(12.4–15.7)

27.9(26.3–29.4)

20.7(18.8–22.6)

28.7(26.2–31.1)

 West

27.5(25.5–29.6)

19.2(17.2–21.2)

14.1(12.4–15.8)

11.4(10.4–12.2)

20.3(18.0–22.6)

17.0(14.5–19.6)

26.3(22.4–30.2)

 p _{for trend}

< 0.001

< 0.001

0.153

< 0.001

< 0.001

< 0.001

0.002

Total

30.5(29.6–31.5)

25.1(24.2–25.9)

14.3(13.7–15.0)

14.3(13.6–14.9)

27.5(26.7–28.4)

25.9(24.8–27.0)

30.7(29.3–32.0)

Weighted Total^†

30.5(29.5–31.4)

26.6(25.8–27.4)

14.0(12.7–15.4)

14.8(13.4–16.2)

30.2(28.4–32.0)

23.7(21.9–25.6)

30.1(27.9–32.2)

Weighted Total^†

31.2(30.2–32.1)

25.2(24.4–26.0)

14.9(14.2–15.6)

15.4(14.7–16.1)

30.1(29.3–31.0)

26.5(25.4–27.5)

30.9(29.6–32.2)