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Duration since last cholesterol check: Grouped years

Codes and Frequencies

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For sample adults, CHOLCHEKYRG reports the last time (in grouped years) the person had a blood cholesterol level check by a doctor, nurse, or other health professional.

This variable was part of annual supplements (Adult Prevention in 1998; Year 2000 in 1993; Health Promotion and Disease Prevention in 1991). For related variables, please use the IPUMS NHIS search function and drop-down menus.


Changes in survey design (e.g., quarters in which the supplement was collected) may affect raw frequencies, but do not affect comparability of the variable. As always, data users should use the prescribed IPUMS NHIS weights.

Because the intervals used to record respondents' answers varies over time, IPUMS NHIS uses a composite coding system for CHOLCHEKYRG to maximize comparability.


The first digit identifies time periods which can be identified in all years: Never (code 1), 1 year or less (code 2), 1 to 2 years (code 3), 2+ years (code 4), and unknown (code 9). The second and third digits identify periods specified for only a subgroup of years.

However, users should be aware of how changes in the exclusive and inclusive nature of response categories impacts the comparability of the composite coding scheme. For example, in 1991, all response categories are inclusive of the smaller year and exclusive of the larger year (i.e., "from 2 years to less than 3 years"). However, in 1998, all response categories are exclusive of the smaller year and inclusive of the larger year (i.e., "Greater than 2 years to 3 years"). Therefore, someone who received a cholesterol check exactly two years ago could be coded to "410 - From 2 years to less than 3 years" in 1991, but could be coded to "320 - Greater than 1 year to 2 years" in 1998. This is important if users choose to use only the first digit of the code, since someone who indicates it has been two years since their last cholesterol check could be collapsed into the "4" category in 1991, but the "3" category in 1998. Users concerned about this level of detail may consider retaining all of the detailed codes instead of only looking at the first digit. Please see the codes tab for the availability of each response category.

Prior to 2019, the questionnaire asked, "About how long has it been since you had your blood cholesterol level checked by a doctor or other health professional?" Beginning in 2019, the question changed slightly to explicitly include nurses: "When was the last time you had your cholesterol checked by a doctor, nurse, or other health professional?"

Comparability will be affected by changes above, changes to the universe over time, and the 2019 redesign. The NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.


  • 1991: Sample persons age 18+.
  • 1993: Half of sample persons age 18+ in quarters 3 and 4 (excluded from Y2K supplement).
  • 1998: Sample adults age 18+.
  • 2019; 2021: Sample adults age 18+.


  • 1991, 1993, 1998, 2019, 2021