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Table 1 Study descriptives

From: DNA methylation biomarker for cumulative lead exposure is associated with Parkinson’s disease

Demographic variable SGPD PEG
PD (n = 959) Control (n = 930) PD (n = 569) Control (n = 238)
Continuous variables: mean (SD)
 Age* 66.5 (9.1) 64.9 (10.4) 70.5 (9.8) 67.5 (12.8)
 European fractional ancestry NA 0.87 (0.27) 0.92 (0.18)
 meanMethBySample 0.26 (0.01) 0.27 (0.01) 0.29 (0.01) 0.29 (0.01)
 DNAm tibia-lead 2.57 (0.41) 2.46 (0.49) 2.65 (0.54) 2.52 (0.52)
 DNAm patella-lead 3.41 (0.4) 3.48 (0.4) 3.06 (0.4) 3.03 (0.3)
Categorical variables: n (%)
 Male 611 (63.7) 428 (46.0) 356 (62.6) 127 (53.4)
 Former smoker NA 240 (42.4) 125 (52.5)
 Current smoker 25 (4.2) 17 (7.1)
  1. *For SGPD, age was not provided in the GEO data. To account for age, we therefore generated the epigenetic age based on the Horvath epigenetic clock (DNAmAge, highly correlated with chronologic age R > 0.9 in other studies of older adults)
  2. NA: All participants with SGPD methylation data are of European ancestry (11). Smoking status data not available for SGPD via data not provided in GEO