Table 1

Baseline characteristics of the total study population and age-adjusted and sex-adjusted mean values or frequencies of potential risk factors for dementia according to quartiles of the total brain volume TBV-to-ICV ratio at baseline

Risk factors at baselineTotal population
(n=1158)
TBV/ICV (%)P for trend
Q1 (71.54–76.81)
(n=289)
Q2 (76.82–78.43)
(n=290)
Q3 (78.44–79.80)
(n=290)
Q4 (79.81–85.48)
(n=289)
Age, years73.6 (6.2)†78.7 (0.3)‡74.9 (0.3)‡71.6 (0.3)‡69.4 (0.3)‡<0.001
Male sex, %44.269.0§50.0§37.0§21.8§<0.001
Education ≤9 years, %35.533.3§35.8§35.5§35.5§0.70
Systolic blood pressure, mm Hg134.0 (18.4)†134.5 (1.2)‡133.7 (1.1)‡134.0 (1.1)‡133.9 (1.2)‡0.97
Diastolic blood pressure, mm Hg76.4 (10.9)†75.9 (0.7)‡76.0 (0.6)‡77.3 (0.6)‡76.5 (0.7)‡0.45
Antihypertensive medication, %54.959.4§59.8§52.1§49.5§0.02
Hypertension, %69.774.1§73.0§67.4§67.2§0.08
Diabetes mellitus, %23.634.6§26.7§18.8§13.6§<0.001
Serum total cholesterol, mmol/L198.1 (35.6)†194.7 (2.2)‡197.1 (2.0)‡199.8 (2.0)‡200.7 (2.2)‡0.29
Body mass index, kg/m223.2 (3.3)†23.0 (0.2)‡23.3 (0.2)‡23.4 (0.2)‡23.0 (0.2)‡0.21
ECG abnormalities, %16.319.0§13.3§15.8§13.8§0.26
Cerebrovascular lesions, %34.737.8§35.0§33.9§28.6§0.07
Smoking habits, %8.97.4§6.4§6.2§3.7§0.08
Alcohol intake, %42.942.4§46.4§37.6§40.8§0.44
Regular exercise, %20.418.5§25.6§17.2§19.9§0.71
MMSE <24, %5.77.4§6.3§4.7§3.8§0.09
Mild cognitive impairment, %13.614.4§15.7§13.4§6.8§0.03
  • Age was adjusted for sex. Sex was adjusted for age.

  • Hypertension was defined as blood pressure ≥140/90 mm Hg and/or current use of antihypertensive medication. ECG abnormalities were defined as Minnesota code 3–1, 4–1, 4–2, 4–3 or 8–3. Regular exercise was defined as engaging in any form of physical exercise three or more times a week during leisure time. Cerebrovascular lesions were defined as brain infarction or haemorrhage on MRI regardless of the presence of absence of neurological symptoms. Smoking habits and alcohol intake were classified as current use or not.

  • †Values are shown as mean (SD).

  • ‡Values are shown as mean (SE) after adjustment for age and sex.

  • §Frequencies were adjusted for age and sex.

  • GMV, grey matter volume; ICV, intracranial volume; MMSE, Mini–Mental Statement Examination; TBV, total brain volume.