Codes and Frequencies
For sample adults who had used high dose or megavitamin therapy (2002) or had taken vitamin or mineral supplements (2007) during the past 12 months (VITYR and VITANY), VITYLCONVHP identifies those who had let a conventional medical professional know about their use of high dose/megavitamin therapy or vitamin/mineral supplements
In 2002, interviewers asked, "During the past 12 months, did you let any of these conventional medical professionals know about your use of high dose or megavitamin therapy?" In 2007, the question was nearly identical but referred to "vitamins" rather than "high dose or megavitamin therapy." In both years, the interviewer then handed the respondent a card listing several types of conventional health care practitioners. If the answer was affirmative (i.e., a "Yes" response in VITYLCONVHP), interviewers asked the follow-up question, "Which ones [did you tell]?" and noted, "You may choose more than one."
The list for 2002 (and the associated IPUMS NHIS variables, which are also present for 2007) included the following medical professionals:
- Medical Doctor (M.D.) (including specialists) (VITYLMD)
- Nurse Practitioner/Physician Assistant (VITYLNURS)
- Psychiatrist (VITLPSYCHI)
- Dentist (including specialists) (VITYLDENT)
The list for 2007 included additional categories of conventional medical professionals, which are shown below with the associated IHIS variables (available for 2007 only):
- Doctor of Osteopathy (D.O.) (VITLDO)
- Psychologist/Social Worker (VITLPSYCHO)
- Pharmacist (VITLPHARM)
For more information about the full range of variables related to vitamins, including a definition of "high dose or megavitamin therapy," see VITYR and VITANY.
As noted in the variable description, the list of conventional medical practitioners on the card shown to respondents was shorter in 2002 than in 2007. Thus, a "No" response under the 2002 question wording might have been a "Yes" response under the 2007 question wording.
For example, persons who had told a pharmacist, doctor of osteopathy, or psychologist or social worker about their use of vitamins would probably have answered "no" to the 2002 question wording but would have answered "yes" to the 2007 question wording for VITYLCONVHP. Researchers should thus exercise caution in comparing results from VITYLCONVHP for 2002 and 2007.
A second difference in VITYLCONVHP between 2002 and 2007 is the number of response categories.
In 2002, the response categories included "Yes," "No," and "Did not go/talk to any of these." These 2002 categories might seem to distinguish persons who did not see any of the listed conventional medical professionals (and thus had no opportunity to report their use of vitamins) from persons who chose not to report their vitamin use to a conventional medical professional. But among persons who answered "No," it is unclear how many meant, "No, I did not tell any of these conventional medical professionals, even though I saw at least one of them" and how many meant, "No, I did not tell any of these conventional medical professionals, and I did not see any of them." Perhaps because of this ambiguity, response categories were limited to "Yes" and "No" in 2007.
To maximize comparability across years without sacrificing detail, IHIS uses composite coding for this variable.
The first digit indicated broad categories of "No" (codes beginning with 1), "Yes" (codes beginning with 2), and "Unknown" (codes beginning with 9). The second digit supplies detail present in only some years, such as distinguishing between "No" (IHIS code 10) and "Did not go/talk to any of these" (IHIS code 11) in 2002. Researchers who wish to maximize comparability between 2002 and 2007 can combine categories beginning with the number 1 into a single "No" category.
A final difference in VITYLCONVHP between 2002 and 2007 occurs in the wording fo the question. In 2002, interviewers asked about the use of "high dose or megavitamin therapy," while in 2007 they asked about the use of "vitamins." Researchers must judge for themselves how seriously this change in wording--and the associated difference in universes for VITYLCONVHP--compromise comparability between 2002 and 2007 for their analyses.
- 2002: Sample adults age 18+ who have used high dose or megavitamin therapy for their own health or treatment during the past 12 months.
- 2007: Sample adults age 18+ who have taken vitamins or mineral during the past 12 months.
- 2002, 2007
- 2002, 2007 : SAMPWEIGHT