National Interview Survey Research Articles

Patterns of nutrient intake among dietary supplement users: Attitudinal and behavioral correlates

A national telephone interview survey of an age-stratified random sample of 2,991 adults, aged 16 and over, provided detailed information from 1,142 vitamin and mineral supplement users about their nutrient intake patterns from dietary supplements. Dietary supplement users were divided into four groups (Light, Moderate, Heavy, and Very Heavy) on the basis of the type and amount of nutrient intake from supplements. The Light, Moderate, Heavy, and Very Heavy nutrient intake groups accounted for 42%, 16%, 28%, and 14%, respectively, of the total users. Young supplement users (aged 16 to 25) tended to be in the Light user group. Older adults (aged 41 to 64) and residents of the western United States tended to be in the Heavy and Very Heavy user groups. Users in the Light and Moderate nutrient intake groups generally used only one broad-spectrum vitamin and mineral product. Users in the Heavy and Very Heavy groups were typically taking two or more specialized vitamin and mineral products at a time as part of a personalized supplement regimen. Heavy and Very Heavy nutrient intakes were associated with more frequent visits to health food stores, greater nutrition activity, and less physician involvement. Light and Moderate nutrient intakes were more likely to be associated with a defensive interest in avoiding nutritional deficiencies. The implications of generally different motivations for dietary supplement use are discussed in the context of public information strategies.

Rates and responses of distressed women to phone survey screening and recruitment.

Telephone interviews were used to assess both the prevalence of psychic distress among women during the past 12 months and the willingness of respondents to participate in a study of how women employ self-change efforts to cope with emotional distress. A second purpose of this research was to demonstrate the general effectiveness of telephone surveys in assessing psychological distress. The major findings indicated that the experience of having been nervous or upset was not uncommon: 64% of the 140 respondents indicated some distress, while 31% had been distressed for more than just a couple of days; also, the majority of distressed women were willing to complete an initial questionnaire (81%), a personal interview (53%), and/or follow-up questionnaires (76%). Respondents who reported greater distress were more willing to participate in the study than were respondents who reported less distress. These findings agree with those of a national household interview survey of psychological distress. Our results suggest that telephone surveys represent an effective alternative method for collecting epidemiological data on the sensitive topic of emotional distress.

Vitamin/mineral supplement use: A telephone survey of adults in the United States ,

Vitamin/mineral supplement use in the United States was assessed through a national telephone interview survey of an age-stratified random sample of 2,991 adults 16 years old and older. A vitamin/mineral supplement was defined as any product containing one or more of 33 specific vitamins, minerals, or "miscellaneous dietary components." Excluding pregnant/lactating women, 39.9% of the population consumed one or more supplements. Of those users, 52.4% consumed one supplement only; 10.9% consumed five or more (up to a maximum of 14 separate products). Confirming other research, above-average consumption of supplements occurred in the western United States. The most widely consumed product type was the single vitamin/miscellaneous dietary component (45.2% of supplement users). Vitamin C, either alone or in combination with other nutrients, was the most widely consumed nutrient (90.6% of supplement users). Use of supplements was more prevalent among women than among men in each of the three age groups examined: 16 to 24 years, 25 to 64 years, and 65 years and older. Although consumption of the B vitamins was more widespread among women than among men, more men than women consumed zinc, iodine, copper, magnesium, and manganese. There was a wide range of intake of both vitamins and minerals, which extended to 10 to 50 times the RDAs for individual nutrients.

Nonresponse on Surveys: A Canada-United States Comparison

This paper compares survey response rates in Canada and the United States. Initial unsystematic evidence suggests a large margin in favour of the United States on national inter- view surveys. Three hypotheses are entertained: that the difference in response rates is attribut- able to fieldwork procedures employed in each country; that the difference reflects socioeconomic differences between Canada and the United States; and that a cultural resistance to surveying depresses Canadian rates of response below the level expected on the basis of the socioeconomic structure of the society. Using response rate per survey as the unit of analysis, Canadian and American samples of response (N = 443), with codes for details on fieldwork procedures, are used to test the hypotheses. National interview surveys in Canada achieve some 10-15 percentage points lower response than comparable surveys in the United States. We can establish about 7 of these points as attrib- utable to factors other than simply the number of call-backs. The remaining margin does seem due to the lower frequency of call-backs in Canadian surveys. We conclude that it would be diffi- cult to greatly increase call-backs in national-scale surveys, given the Canadian realities of geog- raphy, and economy. Alternative methods of data collection, or surveys on the regional or local scale, may hold a comparative advantage in the Canadian context.

Effects of Health Insurance on Physicians' Fees

According to conventional wisdom, the growth of health insurance is partly responsible for the rise in physicians' fees; however, to date, convincing empirical evidence is lacking. A standard model of physician fee determination yields unambiguous predictions about insurance effects on fees. Empirical evidence, based on national interview surveys of physicians, shows insurance does affect fees in the predicted direction. Insurance parameter estimates imply that a $1.00 increase in an insurer's fee schedule raises physicians' fees somewhere between $0.13 and $0.35 on average. The higher fees could be associated with higher quality, an issue discussed in the last section.

Trends in satisfaction with retirement.

A national personal interview survey, repeating some questions asked 8-10 years earlier on post-retirement experiences, finds current retirees somewhat less satisfied with life after retirement than ones interviewed in the 1960s. Dissatisfaction with the retirement experience continues to be associated with health problems and (to some extent) low income.

Contraception and Pregnancy After Dropping Out of Family Planning Clinics: A National Interview Survey in Jamaica.

Abstract A random national sample of 299 clinic dropouts from the Jamaica National Family Planning Program were interviewed at least five months beyond their first missed clinic appointment. Correl...

Contraception and pregnancy after dropping out of family planning clinics: a national interview survey in Jamaica.

Abstract A random national sample of 299 clinic dropouts from the Jamaica National Family Planning Program were interviewed at least five months beyond their first missed clinic appointment. Correlates of early (after 1 or 2 visits) versus late (3+ visits) dropping out, continued contraceptive practice, and pregnancy since visiting the clinic were identified. The Health Belief Model of “compliance” behavior is proposed as an appropriate theoretical basis for future studies of clinic dropouts.

Relationships among indicators of morbidity: Cross national comparisons

The covariation of conceptually different indicators of general morbidity and selected symptom states was examined on the basis of data from a cross national interview survey in twelve study areas in seven countries (WHO/ICS-MCU). Indicators of disability days in the past two weeks, other health problem in the past two weeks, chronic illness, specific symptoms, vision problem, dental problem, and anxiety were used. First, the correlations among the indicators were examined within each study area. Second, the patterns of the correlations were compared across the study areas. Third, the indicators of morbidity were related separately to age and sex, and the resulting patterns of correlations were compared across the study areas. The results of the study suggest that in general there is a low level of relationship among the specific indicators in all the study areas. Morbidity conditions and symptoms increase slightly with age and are somewhat more frequent among females than males in all areas. When the measurement is based on semantically equivalent measures in several different languages, the patterns of the relationships are much alike among adult populations in urban and rural areas of industrialized countries in the Americas and in Europe.