National Health and Nutrition Examination Survey

The Respiratory Disease Section (variable name prefix RDQ) provides interview data for respiratory symptoms that may be related to chronic bronchitis or asthma. The symptoms profiled include cough, phlegm production, and wheezing. Data is also collected on trigger factors for these symptoms, for medical treatment, and for related functional impairments.

Topics:

• History of Cough and Phlegm Production (RDQ031-RDD060).

        12 Month Period Prevalence of:

• Wheezing (RDQ070);
• Frequency of Wheezing Episodes (RDQ080);
• Sleep Disturbance Due to Wheezing (RDQ090);
• Wheezing With Exercise (RDQ100);
• Number of Doctor, Hospital or Emergency Room Visits for Wheezing (RDD120);
• Prescription Medication Taken For Wheezing (RDQ134);
• Limitation of Usual Activities Due to Wheezing (RDQ135);
• Number of Days of Work/School Missed Due to Wheezing (RDQ137);
• Dry Nocturnal Cough (RDQ140); and
• History of Hay Fever (AGQ030).

Questions regarding a history of cough and phlegm production were only administered to Survey Participants ages 40 years and above, except for RDQ140 (History of Dry Nocturnal Cough) which was administered to Survey Participants 1+ years.

The question regarding a history of wheezing (RDQ070) was administered to all survey participants ages 1+ years. If RDQ070 was answered "yes", then the question series RDQ080 through RDQ137 that collected a detailed history of wheeze symptoms was administered. For survey participants with no recent history of wheeze, there were two exceptions to this. In 2012, RDQ100 & RDQ135 were administered to all survey participants ages 3-15 years. This data is released separately as a part of the restricted access Research Data Center data file C_RDQ. Also, RDQ137 was administered to survey participants ages 6 to 69 years (school-age and working-age persons).

These questions were asked, in the home, by trained interviews using the Computer-Assisted Personal Interviewing (CAPI) system.

The CAPI system is programmed with built-in consistency checks to reduce data entry errors. CAPI also uses online help screens to assist interviewers in defining key terms used in the questionnaire.

For certain variables, all data values at or above a specified level were combined into one category and given the same numeric code. When a variable was modified this way in the data editing process, the third letter in the variable name was changed from a Q to a D (i.e., RDQ changes to RDD). This occurred for the following variables in 2009-12 RDQ:
For RDQ040 and RDQ060, values of 70 years or more were combined and given the code of 70 years. The variables were renamed RDD040 and RDD060 respectively. For RDQ120, values of 20 visits or more were combined and given the code of 20 visits. The variable was renamed RDD120.

These data were collected as part of the NHANES Household Questionnaire Interview. NHANES Household Interview weights should be used if only questionnaire data is analyzed. However, if RDQ_G questionnaire data is merged with MEC examination or laboratory data, then NHANES MEC examination or appropriate subsample sample weights should be used for the analyses.

Current NHANES questionnaire data collection, relating to respiratory symptoms, is based on prior NHANES surveys as well as validated survey instruments (Bellia et al., 2003; Ferris, 1978). It is recommended that data analysts be familiar with current practice and issues in the epidemiologic investigation of respiratory disease (Celli et al., 2005; Halbert et al., 2005; Pauwels et al., 2001; Pierce et al, 1998).

Related Datasets:

In the single survey year 2012, if a participant was between 3 and 15 years of age and answered "No," "Refused," or "Don’t know" to RDQ070 then the questions RDQ100 and RDQ135 were also asked. This data is not publicly released as a part of RDQ_G, rather it is available in the restricted access dataset NHANES/NYFS 2012 C_RDQ.

Related NHANES 2011-2012 Questionnaire Datasets:

Medical Conditions (MCQ) contains questionnaire data on a history of a previous medical provider diagnosis of respiratory disease (asthma, chronic bronchitis, emphysema), age at onset of disease, and family history of asthma.

Physical Functioning (PFQ) contains data on functional physical limitations, as well as information on the type of health problems (including respiratory disease) causing the difficulty.

Cardiovascular Disease (CDQ) contains data for dyspnea (shortness of breath) on exertion for adults ages 40+ years.

Smoking (SMQ) contains data on history of smoking.

Occupation (OCQ) includes data on current and longest occupation, as well as identification of a survey participants exposure to second-hand smoke in their current job (OCQ275).

Prescription Medications (RXQ) contains data on all prescription medications currently taken, including those for asthma, chronic obstructive pulmonary disease (COPD) and other respiratory disorders.

Please note that the question regarding hay fever (AGQ030) was also asked in the NHANES 2007-10 survey cycle RDQ questionnaire section, and in the NHANES 2005-06 survey cycle as a part of the 2005-06 Allergy Questionnaire.

Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.