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. 2019 Sep 11;79(7):684–698. doi: 10.1002/dneu.22715

Table 1.

Overview of demographic data, plasma amyloid levels (pg/ml) and methodology of studies included in our meta‐analyses in alphabetic order of first author names

Study Subjects m f Age Plasma Aβ42 Plasma Aβ40 Aβ42/Aβ40 Methods Study design Data used in meta‐analyses
n n n mean ± SD mean ± SD mean ± SD mean ± SD
Coppus et al. (2012) DS 264 169 95 50.6 ± 4.4 51 ± 14.8 326.4 ± 101.3 0.16 ± 0.05 xMAP technology (Innogenetics) Longitudinal clinical assessments: plasma samples collected at baseline only

Groups: DS versus DS.D

  • DS.D = AD at baseline
DS.D 62 36 26 54 ± 5.9 50 ± 17.5 352.3 ± 103.5 0.15 ± 0.06 Aβ values from baseline
Fortea et al. (2018) DS 233       14.12 ± 3.18 343.83 ± 60.95   Simoa Cross‐sectional design
Groups: DS versus DS.D
  • DS = aDS +pDS
  • DS.D = DS.D
DS.D 49 28 21 54.88*, * 14.79 ± 3.42 384.39 ± 79.87
Fortea et al. (2018) DS 194 105 89 37.05*, * 14.22 ± 3.12 341.52 ± 60.19   Simoa Cross‐sectional design
Groups: DS versus NC
  • DS = aDS
  • NC = NC
NC 67 20 47 52.02*, * 9.41 ± 1.51 196.77 ± 26.58
Head et al. (2011) DS 26 17 9 45.1 ± 9.67 20.59 ± 8.27 275.76 ± 104.63 0.09 ± 0.102 ELISA: BAN50 + BC05/ BA27 Cross‐sectional design Groups: DS versus DS.D
DS.D 52 26 26 53.3 ± 5.05 23.78 ± 17.22 289.61 ± 98.96 0.08 ± 0.072
Head et al. (2011) DS 17 9 8 44.1 ± 5.77 32.88 ± 18.57 327.71 ± 117.80 0.10 ± 0.041 ELISA: BAN50 + BC05/ BA27 Cross‐sectional design
Groups: DS versus NC
  • NC = Young Controls
NC 11 5 6 46.5 ± 6.63 19.82 ± 6.72 196.97 ± 40.20 0.10 ± 0.033
Iulita et al. (2016) DS 21 10 11 34 ± 9.62 16.62 ± 7.79 228.4 ± 109.065   ELISA: Multi‐ Longitudinal Groups: DS versus DS.D
DS.D 10 6 4 52 ± 6.32 17.75 ± 7.27 258.5 ± 93.29   spot V‐PLEX Aβ peptide Panel (6E10) design; plasma samples and clinical data collected at multiple visits

  • DS.D = AD at baseline

Aβ values from baseline
NC 31 16 15 38 ± 11.14 9.14 ± 5.01 90.17 ± 46.77
Jones et al. (2009) DS 39     48.8 ± 7.62 27.07 ± 11.43 121.32 ± 50.71   ELISA (commercial biosource) Cross‐sectional design Groups: DS versus DS.D
DS.D 21     54 ± 5.045 27.85 ± 16.63 125.6 ± 84.14
Matsuoka et al. (2009) DS 145 89** 59** 54.2 ± 3.6** 1,527.03 ± 2,599.10 1,246.75 ± 1,662.34   ELISA: 82E1 + 1C3/ 1A10 Cross‐sectional design (using data from a longitudinal study on vitamin E) Groups: DS versus DS.D
DS.D 52 33 19 56 ± 3.9 1,887.34 ± 2,972.97 1,047.62 ± 1,389.61
Prasher et al. (2010) DS 83 52 31 49 ± 10.2 33.8 ± 15 177.8 ± 67.8 0.23 ± 0.23 ELISA: 6E10 + R165/ R162 Longitudinal cognitive assessments; plasma samples collected at last visit only
Groups: DS versus DS.D
  • DS.D = AD at follow‐up
DS.D 44 30 14 56.8 ± 4.9 33.2 ± 15.9 179.6 ± 59.7 0.21 ± 0.13
Schupf et al. (2001) DS 97     51.9 ± 6.6 22.4 ± 6.1 132.1 ± 44.4   ELISA: 6E10 + R165/ R162 Cross‐sectional design Groups: DS versus DS.D
NC 64 51.5 ± 7.1 14.2 ± 4.5 84.7 ± 19.6
Schupf et al. ( 2010) DS 164 55 109 50.3 ± 5.2 33.4 ± 8.59 150.1 ± 53.79 0.25 ± 0.13 ELISA: 6E10 + R165/ R162 Longitudinal design with DS subjects without AD at baseline; plasma samples collected at multiple visits
Groups: DS versus DS.D
  • DS.D = Incident AD at follow‐up
DS.D 61 18 43 53.7 ± 5.4 25.8 ± 21.77 172.1 ± 52.33 0.16 ± 0.08 Aβ values from follow‐up
Startin et al. (2019) DS 24 17 7 45.25 ± 10.90 25.42 ± 8.46 308.93 ± 105.75 0.086 ± 0.019 Simoa Cross‐sectional design Groups: DS versus DS.D
DS.D 7 5 2 52 ± 10.36 27.07 ± 8.19 363.71 ± 116.14 0.076 ± 0.015
Startin et al. (2019) DS 31 22 9 46.77 ± 10.99 25.79 ± 8.29 321.30 ± 108.69 0.083 ± 0.019 Simoa Cross‐sectional design Groups: DS versus NC
NC 27 16 11 49.26 ± 10.4 15.72 ± 7.43 148.39 ± 75.75 0.110 ± 0.023

The studies by Head et al. (2011), Fortea et al. (2018), and Startin et al. (2019) were split into two rows each due to the use of different samples for comparisons of DS versus NC and DS.D versus DS groups. All amyloid values have been converted to pg/ml whenever necessary, using 1 pg/mL = 0.222 pmol/L for Aβ42 and 0.231 pmol/L for Aβ40. Values reported as standard errors (SE) were converted to SD: SD = SE * √n.

Abbreviations: AD = Alzheimer's disease; aDS = DS subjects who are asymptomatic for AD; Down syndrome; DS.D = Down syndrome with dementia; NC = normal controls, pDS = DS subjects who are in the prodromal stage of AD but do not fulfil criteria for AD diagnosis; SD = standard deviation.

*

Indicates median values;

**

Values were calculated for a total of 148 subjects, not 145 (3 were subsequently excluded).