TABLE 1.
Basic characteristics of the genotyped participants in the selected studies
| Sample | Ntotal | AD cases (%) | Men (%) | Birth year mean (SD) | Age at the end of follow‐up mean (SD), years | Follow‐up through |
|---|---|---|---|---|---|---|
| LOADFS | 3999 | 1973(49.3) | 1491(37.3) | 1928.3 (12.5) | 76.7 (12.5) | 2015 |
| HRS | 7226 | 263 (3.6) | 3129 (43.3) | 1934.2 (8.4) | 79.1 (8.1) | 2012 |
| CHS | 4273 | 247 (5.8) | 1864 (43.6) | 1914.1 (5.7) | 83.5 (5.4) | 2002 |
| FHS | 3625 | 306 (8.4) | 1862 (51.4) | 1931.6 (12.7) | 76.2 (11.1) | 2012 |
Ntotal is total number of subjects in the analysis; AD cases: the number of Alzheimer's disease cases.
Abbreviations: SD, standard deviation; LOADFS, the National Institute on Aging Late‐Onset Alzheimer's Disease Family Study; HRS, Health and Retirement Study; CHS, Cardiovascular Health Study; FHS, Framingham Heart Study parental and offspring cohorts.
LOADFS is a study with a case‐control design that explains a large proportion of AD cases. The other studies are of longitudinal design following the study participants for long periods of time. HRS is a population‐based study, whereas FHS and CHS are community‐based studies. All studies included AD‐affected and unaffected subjects and, therefore, they could be separated into the samples according to the affection status to be used in the comparative analyses of co‐skewness.