Codes and Frequencies
For sample adults in 1987, 1992 and 2000 who had taken calcium during at least 1 month of the past 12 months (VITACALCMO), VITACALCDMO reports the number of days per month respondents had taken calcium.
For 2000, the National Center for Health Statistics (NCHS) used the information recorded in two separate variables--one reporting the time period selected by the respondent (VITACALCTP), and the other reporting the number of days per week or month reported (VITACALCNO)--to create the new recoded variable VITACALCDMO with a single time unit of times per month. VITACALCTP and VITACALCNO record responses to the question, "During [the/those] month(s), about how many [days [per week]/days per month] did you take calcium?"
Also for 2000 only, the NCHS used data from VITACALCTP and VITACALCNO to create a second recoded variable with a single time unit, VITACALCDWK, which reports the number of days per week respondents had taken calcium during the relevant months of the past 12 months.
For 1987 and 1992, VITACALCDMO is not a recoded variable. In those years, respondents who had taken calcium supplements in the past 12 months (VITACALCMO) were asked to report their calcium supplement usage in terms of days per month, rather than responding as desired in terms of days per week or days per month.
As noted in the description of this variable, VITACALCDMO was directly reported in 1987 and 1992. In 2000, this variable was created by the NCHS, using a formula to convert data from other variables on the "time period" and "number of units in a time period" for calcium consumption.
The differing data collection methods yield somewhat different patterns of "heaping" at particular digits between 1 and 31 (1987 and 1992) or 1 and 30 (2000). Due to the pronounced heaping at some points in the distribution, analysts may wish to regroup the data for VITACALCDMO into broad categories (such as "at least every other day" or weekly groupings).
- 1987: Half of sample persons age 18+ (excluded from CACT supplement) who took vitamin/mineral supplements and took calcium in the past 12 months.
- 1992: Half of sample persons age 18+ in quarters 1 and 2, and in 2 weeks of quarter 3 (excluded from CAEP supplement) who took calcium in past 12 months.
- 2000: Sample adults age 18+ who took calcium in past 12 months.
- 1987, 1992, 2000
- 1987, 1992, 2000 : SAMPWEIGHT