First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.

First, an oral, face-to-face interview usually conducted in the respondent's home. These personal interviews were held by trained interviewers with a standardized questionnaire. Second, respondents were also given a questionnaire to fill out. People unable to fill out the questionnaire on their own had the opportunity of doing so with the help of the interviewer. During the face-to-face interview, two tests were conducted starting from 2008 : the digit-symbol test assesses the participants’ “psychomotor speed”, and a peak-flow-meter is used in order to measure the respondents’ lung capacity.