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Table 1 Descriptive characteristics of the study population

From: Subjective cognitive decline and subsequent dementia: a nationwide cohort study of 579,710 people aged 66 years in South Korea

 

Total (n = 579,710)

Non-SCD group (n = 357,654)

SCD group (n = 222,056)

P value

Sex

   

< 0.0001

 Male

266,311 (45.9%)

173,795 (48.6%)

92,516 (41.7%)

 

 Female

313,399 (54.1%)

183,859 (51.4%)

129,540 (58.3%)

 

Income

   

< 0.0001

 Medicaid aid

33,023 (5.7%)

19,101 (5.3%)

13,922 (6.3%)

 

 Group 1 (1st to 6th ventiles)

125,064 (21.6%)

82,491 (23.1%)

42,573 (19.2%)

 

 Group 2 (7th to 14th ventiles)

178,625 (30.8%)

110,550 (30.9%)

68,075 (30.7%)

 

 Group 3 (15th to 20th ventiles)

242,998 (41.9%)

145,512 (40.7%)

97,486 (43.9%)

 

Lifestyle factors

 Smoking status

   

< 0.0001

  Never smoked

406,103 (70.1%)

250,238 (70.0%)

155,865 (70.2%)

 

  Ex-smoker

95,502 (16.5%)

57,647 (16.1%)

37,855 (17.0%)

 

  Current smoker

78,105 (13.5%)

49,769 (13.9%)

28,336 (12.8%)

 

 Alcohol consumption

   

< 0.0001

  No drinking: rarely

508,547 (87.7%)

314,324 (87.9%)

194,223 (87.5%)

 

  Light drinking: 3–4 times per week

38,840 (6.7%)

23,954 (6.7%)

14,886 (6.7%)

 

  Heavy drinking: almost every day

32,323 (5.6%)

19,376 (5.4%)

12,947 (5.8%)

 

 Exercise frequency

   

< 0.0001

  Exercise

327,775 (56.5%)

200,723 (56.1%)

127,052 (57.2%)

 

  No exercise

251,935 (43.5%)

156,931 (43.9%)

95,004 (42.8%)

 

Healthcare visit frequency*

 First quartile

144,858 (25.0%)

93,542 (26.2%)

51,316 (23.1%)

 

 Second quartile

144,945 (25.0%)

89,583 (25.1%)

55,362 (24.9%)

 

 Third quartile

144,988 (25.0%)

88,208 (24.7%)

56,780 (25.6%)

 

 Fourth quartile

144,919 (25.0%)

86,321 (24.1%)

58,598 (26.4%)

 

Past medical history

 Psychiatric disorders

  Depression

48,653 (8.4%)

26,676 (7.5%)

21,977 (9.9%)

< 0.0001

  Bipolar affective disorder

1891 (0.3%)

1059 (0.3%)

832 (0.4%)

< 0.0001

  Substance use disorder

3522 (0.6%)

2035 (0.6%)

1487 (0.7%)

< 0.0001

  Panic disorder

2315 (0.4%)

1298 (0.4%)

1017 (0.5%)

< 0.0001

  Obsessive-compulsive disorder

671 (0.1%)

370 (0.1%)

301 (0.1%)

0.001

  Personality disorder

237 (0.0%)

142 (0.0%)

95 (0.0%)

0.619

  Other psychiatric disorders

140,212 (24.2%)

81,764 (22.9%)

58,448 (26.3%)

< 0.0001

 Neurological diseases

  Cerebrovascular disease

80,212 (13.8%)

46,895 (13.1%)

33,317 (15.0%)

< 0.0001

  Epilepsy

8622 (1.5%)

4807 (1.3%)

3815 (1.7%)

< 0.0001

  Migraines

43,466 (7.5%)

25,304 (7.1%)

18,162 (8.2%)

< 0.0001

  Headaches

70,207 (12.1%)

40,791 (11.4%)

29,416 (13.2%)

< 0.0001

  Sleep disorder

63,769 (11.0%)

36,635 (10.2%)

27,134 (12.2%)

< 0.0001

  Head injury

64,698 (11.2%)

39,459 (11.0%)

25,239 (11.4%)

< 0.0001

 Medical diseases

  Diabetes mellitus

154,977 (26.7%)

94,346 (26.4%)

60,631 (27.3%)

< 0.0001

  Myocardial infarction

8504 (1.5%)

5245 (1.5%)

3259 (1.5%)

0.981

  Congestive heart failure

31,952 (5.5%)

19,222 (5.4%)

12,730 (5.7%)

< 0.0001

  Liver disease

146,020 (25.2%)

88,392 (24.7%)

57,628 (26.0%)

< 0.0001

  Renal disease

5669 (1.0%)

3476 (1.0%)

2193 (1.0%)

0.564

  Peptic ulcer disease

259,797 (44.8%)

155,929 (43.6%)

103,868 (46.8%)

< 0.0001

  Thyroid gland disorder

40,236 (6.9%)

23,104 (6.5%)

17,132 (7.7%)

< 0.0001

  Asthma

123,850 (21.4%)

74,598 (20.9%)

49,252 (22.2%)

< 0.0001

  Cancer

41,290 (7.1%)

24,845 (6.9%)

16,445 (7.4%)

< 0.0001

 Medication history

  HMG-CoA reductase inhibitors

128,527 (22.2%)

77,725 (21.7%)

50,802 (22.9%)

< 0.0001

  Diabetes medication

84,015 (14.5%)

51,878 (14.5%)

32,137 (14.5%)

0.735

  Antihypertensive medication

288,262 (49.7%)

178,093 (49.8%)

110,169 (49.6%)

0.180

  Antidepressants

31,079 (5.4%)

17,216 (4.8%)

13,863 (6.2%)

< 0.0001

  Benzodiazepines and sleeping pills

92,444 (15.9%)

53,108 (14.8%)

39,336 (17.7%)

< 0.0001

  Antiplatelet medication

140,615 (24.3%)

86,071 (24.1%)

54,544 (24.6%)

< 0.0001

 Depression Screening Questionnaire score, mean (SD)

0.34 (0.79)

0.23 (0.67)

0.53 (0.92)

< 0.0001

Laboratory findings

 Cholesterol level, mean (SD), mg/dL

  LDL cholesterol

117.47 (35.58)

117.26 (35.55)

117.81 (35.64)

< 0.0001

  HDL cholesterol

53.63 (13.64)

53.57 (13.61)

53.73 (13.68)

< 0.0001

  Triglycerides

134.31 (70.64)

134.80 (70.97)

133.54 (70.10)

< 0.0001

  Fasting glucose

101.89 (20.96)

102.11 (21.10)

101.52 (20.73)

< 0.0001

  Hemoglobin

13.59 (1.40)

13.63 (1.40)

13.54 (1.39)

< 0.0001

 Physical examination findings

  Body mass index

24.29 (2.98)

24.31 (2.99)

24.25 (2.98)

< 0.0001

  Systolic blood pressure

128.74 (15.43)

129.05 (15.44)

128.22 (15.41)

< 0.0001

  Diastolic blood pressure

78.01 (9.73)

78.18 (9.73)

77.73 (9.73)

< 0.0001

  1. HDL high-density lipoprotein, LDL low-density lipoprotein, SCD subjective cognitive decline, SD standard deviation
  2. *The fourth quartile group had the highest frequency of medical visits