Table 1

Characteristics of the three longitudinal studies

Author
Population Baseline numbers Descriptives Length of follow up [fu]
Type of study, main outcome
Measurement of cognition/dementia
Measurement of haemoglobin [hb]/anaemia
Adjusted for:
Relationship with haemoglobin [hb]/anaemia
Statistics if available. OR = Odds Ratio, RR = Relative Risk, HR = Hazard Ratio, (numbers in brackets are 95% confidence intervals) In order to assess the most conservative finding, results used are those from the adjusted analyses unless otherwise stated.

Atti et al [19]
Kungsholmen project, Sweden
1435 people without dementia at baseline
Aged 75–95 years
Mean fu 3.4(0.5 SD) years
Cohort Dementia
Clinical exam, review by specialist using DSM-III-R – dementia information on those who died in follow up from death certificates and medical records
WHO criteria 130 g/L men, 120 g/L women Plus: Lowest 25th percentile 135 d/L men & 129 g/L women and lowest 5th percentile 117 g/L & 116 g/L women
In those with MMSE >= 26: Age, sex, education, history of hypertension, diabetes, cerebrovascular disease, heart failure, chronic coronary disease, COPD, hypothyroidism, chronic renal failure, high white blood cells, high blood sedimentation rate, low albumin, low BMI.
Anaemia increases risk of dementia in those with MMSE >= 26
Low Hb-below 130 g/L men & 120 g/L women increases risk of dementia
In addition in subjects with MMSE >= 26....
With Hb < 25th percentile HR 1.2 (0.7–2.0)
With Hb WHO criteria HR 2.0 (1.0–3.8)
With Hb < 5th percentile HR 2.2 (1.0–4.9)
Atkinson et al [21]
Women's health & ageing study 1, USA
558 women with MMSE > 24 and walking speed > 0.4 m/s.
Mean age of whole study = 78 yrs(SD8.1)
Fu 3 years
Cohort Cognitive decline (fall in MMSE to < 24)
MMSE
Hb(g/dl)
Age, race, smoking, education, no diseases, pulmonary disease, hb, baseline walking speed, baseline MMSE, baseline IADL, baseline ADL
Hb not significant association with cognitive decline
Cognitive decline
OR 0.86 (0.60–1.21)
Combined physical and cognitive decline
OR 0.68 (0.47–0.98)
C.Mary Beard et al [20]
Minnesota 1. 302 incident cases of Alzheimer's Disease [AD] with matched controls. (255 pairs analysed) Fu: Hb from year preceding or year of dementia onset.
1. Retrospective case-control
1. AD identified from lists of diagnostic terms thought to include dementia – diagnostic criteria similar to DSM. controls matched by age and gender.
WHO criteria 130 g/L men, 120 g/L women.
1. Lowest measurement recorded in 2 yr window (onset + preceding yr) for cases and corresponding for controls.
1. age, gender
1. Anaemia increases risk of AD (not significant in men)
1.OR 188 (1.17–3.03)
Men OR 1.81 (0.75–4.39)
Women OR 1.96 (1.11–3.47)

2. 618 people Aged 65 years+ Fu: 5.1 years (1 day-7.9 years)
2. Cohort Alzheimer's disease [AD]
2. Medical records reviewed by nurse abstractor and confirmed by author
2. A value below WHO criteria between 1985 & 1989

2.No association between anaemia and AD
2.SIR 0.98 (0.67–1.37)
Men SIR 1.49 (0.79–2.56)
Women SIR 0.79 (0.49–1.23)

Peters et al. BMC Geriatrics 2008 8:18   doi:10.1186/1471-2318-8-18