Table 1 Characteristics of the three longitudinal studies
From: Haemoglobin, anaemia, dementia and cognitive decline in the elderly, a systematic review
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) |