Codes and Frequencies
CONSTIPYRC indicates whether the person had chronic frequent constipation in the past year. This variable is created with supplemental programming by the IPUMS NHIS staff from the pre-1997 condition records. For general information about IHIS variables (such as CONSTIPYRC) created from the pre-1997 condition records, see the User Note on Condition Records and Condition Variables.
Defining Constipation Records and Identifying Persons with Constipation
For all available years, persons with this condition are identified through a direct question about having constipation. Until 1981, a person could also have a record for this condition through an indirect question, such as a reason for a doctor's visit. In 1972-1981, codes of "21" and "22" are used to identify the different sources of the information. For 1996 forward, persons who were not asked a direct question about constipation, or for whom it is unknown whether they were asked such a question, are given a code of "NIU" (not in universe), regardless of whether they have a chronic constipation record.
For 1975 and 1978-1981, constipation records were defined as those condition records with a code of "172" ("Constipation") in the variable DIAGR1 in the original NHIS public use files. These condition code values come from NCHS's Diagnostic Recode #1: Diseases, Injuries, and Impairments, not from the International Classification of Diseases (ICD) codes. Additionally, to be considered "chronic," constipation condition records must have a code of "1" ("Chronic") in the variable CACODE in the original NHIS public use files.
For 1982 to 1996, chronic constipation records were defined as those condition records with a code of "314" ("Constipation") in the variable C1CONDRC in the original NHIS public use files. This condition code value comes from NCHS's Diagnostic Recode C: Chronic Conditions and Impairments.
Related Constipation Variables
The nearest equivalent of CONSTIPYRC available after 1996 is CONSTIPYR (Had recurring constipation, past 12 months). However, researchers should use caution when comparing prevalence estimates derived from these two variables, as the manner of collecting information about constipation differs greatly between the two. CONSTIPYRC was created by recoding condition records that were generated in response to several different survey questions about health problems underlying disability, sick days, or contacts with health care practitioners. CONSTIPYR, by contrast, is based on a direct question about whether the person had the condition constipation.
As with all of the person-level condition variables created by IHIS from condition records prior to 1997, the universe for CONSTIPYRC is substantially different for 1978 forward than it is for years prior to 1978. Beginning in 1978, only persons living in 1/6 of households, rather than all persons, were asked a direct question about having constipation in the past year. There is also a minor universe change between the sets of years 1978-1981 and 1982-1996. These changes require that different weight variables be used depending on which years of data are analyzed. See the "Description" tab for details.
Additionally, there is a change in the way "Yes" responses are coded over time. See the User Note on Condition Records and Condition Variables for details about the composite coding scheme employed by IHIS.
- 1975: All persons.
- 1978-1981: Persons living in 1/6 of households (who received Condition List 1).
- 1982-1996: Persons living in 1/6 of households (who received Condition List 3).
- 1975, 1978-1996