The National Long Term Care Survey (NLTCS) is a nationally-representative multi-stage probability sample of 49,258 Medicare enrollees aged 65+, initiated in 1982, followed longitudinally, nominally at five-year intervals, with sample replenishment during 1984–2004.
In 2000–2002, biospecimen samples were collected from 1,811 NLTCS participants in the 1999 NLTCS survey and 869 non-participant siblings (forming 386 sib sets). Of the 1,811 primary participants, 918 were classified as disabled using standard NLTCS classification protocols and were selected for SNP array genotyping.
Of the 918 disabled participants in the 1999 NLTCS, 913 participants yielded usable SNP array genotyping data using the Illumina Infinium Omni2.5-8 BeadChip, with 2,372,784 SNP markers each. The SNP array analysis was conducted at the Northwest Genomics Center (NWGC) at the University of Washington, Seattle, WA.