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Technical Notes 2000

Behavioral Risk Factor Surveillance System (BRFSS)

Weighted BRFSS data are used in all calculations. BRFSS data are weighted for the probability of selection of a telephone number, the number of adults in a household, and the number of phones in a household and adjusted to reflect the demographic distribution of North Carolina's adult population (ages 18 and older).

Respondents who refused to answer or did not know the answer were excluded in any calculations in these tables. The denominator for each calculation is the number of adults who responded to the item (exceptions are specified in the footnotes). All questions from the survey are not presented in the following tables; however, the full questionnaire may be viewed online. Whenever possible, the exact wording for each question is used as a title, however due to space limitations, the titles may not include some introductory remarks and explanations for some questions.

Derived Risk Factors in the BRFSS

Acute Drinking

  • At risk: Respondents who reported that they have had alcoholic beverages in the past month and have had five or more alcoholic drinks on one or more occasions in the past month.
  • Not at risk: Respondents who have not had any alcoholic beverages in the past month or respondents who have had alcoholic beverages but have not had five or more drinks on an occasion.

Cholesterol Awareness

  • At risk: Were checked five or more years ago or never checked.
  • Not at risk: Respondents who had blood cholesterol checked and had been checked in past five years.

Chronic Drinking

  • Derived by calculating the total number of drinks consumed per month: number of drinks per month = number of days respondent drank alcohol X number of drinks per occasion.
  • At risk: Respondents who reported that they have had on the average two or more drinks per day i.e., 60 or more drinks a month.
  • Not at risk: Respondents who reported that they have not had any alcoholic beverages in the past month or respondents who reported that they have not had greater than 60 drinks a month.

Cigarette Use

  • At risk: Respondents who reported that they have smoked at least 100 cigarettes in their lifetime and now smoke (everyday or some days).
  • Not at risk: Respondents who reported that they have not smoked 100 cigarettes in their lifetime or respondents who have smoked 100 cigarettes in their lifetime but currently do not smoke.

Drinking and Driving

  • At risk: Respondents who reported that they have had alcoholic beverages in the past month and have driven after having too much to drink one or more times in the past month.
  • Not at risk: Respondents who reported that they have not had any alcoholic beverages in the past month or respondents who reported that they have had alcoholic beverages in the past month but have not driven a car after having too much to drink.

Exercise

  • At risk: Respondents who reported no physical activity or who reported physical activities that were done for less than 30 minutes, or fewer than five times per week, or both.
  • Not at risk: Respondents who reported a physical activity that were done for 30 minutes or more per session, five or more times per week, regardless of intensity.

Hypertension

  • At risk: Respondents who reported that they have been told that their blood pressure is high (one or more times).
  • Not at risk: Respondents who reported that they have not been told that their blood pressure is high.

Hypertension Awareness

  • At risk: Respondents blood pressure was never checked or not checked within the past two years.
  • Not at risk: Respondents who reported they have their blood pressure checked within the past two years.

Overweight

  • Derived from the body mass index. Body mass index is computed as weight in kilograms divided by height in meters squared: (weight¬†/¬†height2). BMI is an intermediate variable used in calculating this measure.
  • At risk: Body mass index greater than or equal to 25.0.
  • Not at risk: Body mass index less than 25.0.

Safety Belt Usage

  • At risk: Respondents who reported that they "nearly always," "sometimes," "seldom," or "never" wear seat belts when driving or riding in a car.
  • Not at risk: Respondents who reported that they "always" wear seat belts when they drive or ride in a car or "never drive or ride in a car."

Smokeless Tobacco

  • At risk: Respondents who reported that they have used smokeless tobacco products and currently use smokeless tobacco products.
  • Not at risk: Respondents who reported that they have not used smokeless tobacco products or respondents who have used smokeless tobacco products, but currently do not use smokeless tobacco products.

Physical Inactivity/Activity

  • Physically inactive: No reported activity.
  • Irregular activity: Any physical activity done for less than 20 minutes or less than three times per week.
  • Regular activity: Any physical activity done for a total of 20 or more minutes three or more times per week, at less than 50% of functional cardio-respiratory conditioning capacity.
  • Regular and vigorous activity: Any physical activity that requires rhythmic contraction of large muscle groups at 50% of functional cardio-respiratory conditioning capacity for 20 or more minutes three or more times per week.

Fruit and vegetable consumption

  • Derived from all questions in the entire fruit and vegetable module

Strengths and Limitations of the Survey Data

There are some significant advantages of the telephone survey methodology, including better quality control over data collection made possible by a computer-assisted-telephone-interviewing system, relatively low cost, and speed of data collection. The BRFSS methodology has been used and evaluated by the CDC and participating states since 1984. The content of the survey questions, questionnaire design, data collection procedures, interviewing techniques, and editing procedures have been carefully developed to improve data quality and lessen the potential for bias. The data collection is ongoing and each year new annual results become available.

One limitation of a telephone survey is the lack of coverage of persons who live in households without a telephone. Households without a telephone are, on average, of lower income. Therefore, for many of the health risks shown in this report, the results are likely to understate the true level of risk in the total population of adults in North Carolina. Since approximately 95 percent of households in North Carolina do have one or more telephones, the degree of understatement is probably not large.

A second limitation is due to the fact that the data are self-reported by the respondents. We expect that respondents tend to underreport health risk behaviors, especially those that are illegal or socially unacceptable.