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. Author manuscript; available in PMC: 2017 Sep 8.
Published in final edited form as: Neuroepidemiology. 2016 Sep 8;47(2):67–75. doi: 10.1159/000443277

Table 2.

Reasons for missing data

N = 1,033
Electrocardiogram (ECG) missing N = 29 (2.8%)
 Technical/transmission errors (all)

Lab assays missing N = 7 (0.6%)
 Sample contamination 4
 Refusal of blood draw 2
 Inability to draw blood 1

Neurocognitive tests missing N = 3 (0.3%)
 Incomplete clinical exam (all)

MRI missing N = 35 (3.4%)
 Deemed ineligible at clinic visit 22
 Excess motion/poor image quality 9
 Image corruption/data loss 4

Withdrew data after examination N = 215 (20.8%)