Table 1. Activity of G1 (the cohort of index children) and illustrative data availability in ALSPAC.

G1 Activity as of February 2019	n
Currently active in study *	13,286
Known address	9,856
Can send Qs	8,964
Can send clinic invites	9,306
Linked to Primary health care data	11,810
Linked to Secondary health care data	12,700
At least one DXA ** measure between the ages of 7 and 24	9,144
Genomics data	8,952
Methylation at multiple time points	1,003
G2 parent 3	548

DXA - Dual-energy X-ray absorptiometry, G2 - the cohort of offspring of the index children

*still alive, not withdrawn, not explicitly opted out

**Body composition assessed using Dual-energy X-ray absorptiometry