Field examination stages
Field investigation methods have been described in detail in the reports Aromaa et al. 1985, 1989a, Lehtinen et al. 1985, and Sievers et al. 1985. The investigation had three stages: the health interview, the basic health examination, and the clinical health examination.
Health interview: An trained nurse – normally a local nurse – visited the participant generally 1-6 weeks before the health examination. She carried out a standard interview including 120 questions about the following topics: personal data, health status, chronic diseases, handicap, mental health, usage of health services, use of medicine, dentist visits and dental condition, earlier health examinations, smoking and use of food (MS124).
Basic health examination: The Finnish Mobile Clinic carried out a basic health examination about 1-6 weeks after the health interview. The persons included in the sample were invited via letter a couple of weeks before the suggested examination time. Alongside the invitation, they were sent a basic questionnaire (MS011). It consisted of 107 questions which considered amongst other things health, diseases, their treatment, work, work conditions, hobbies, exercise, accomplishment of usual activities, and use of alcohol. In case some questions were not answered, the Finnish Mobile Clinic nurse filled the questionnaire with the help of an interview.
The basic examination program included taking blood and urine samples, measuring height, weight, and skinfolds, blood pressure and the pulse, chest X-ray, resting ECG, spirometry, joint functioning examination (MS014), and toot examination (Vehkalahti et al. 1991). At the basic examination, the participants filled a food questionnaire (MS053), a friendship and family relationships questionnaire (MS016) and a questionnaire regarding mental symptoms (MS019). Heart and respiratory organ symptom interview (MS010) and musculoskeletal disease symptom interview (MS015) were carried out for all participants. Additional disease specific interviews were carried out for those reporting diabetes, heart disease, stroke, lower limb arterial disease, hypertension or digitalis or nitrate medication in the basic questionnaire.
MS010 Cardiovascular diseases and respiratory track symptoms interview
MS011 Basic questionnaire
MS014 Joint function examination
MS015 Musculoskeletal disease; symptom interview
MS016 Friendship and family relationships questionnaire
MS019 Symptom questionnaire; mental health
MS053 Food questionnaire
Clinical health examination: The basic health examination worked as a screening instrument, based on which part of the participants was invited to a clinical health examination after a couple of months (in average 3.5 months). The screening methods were compiled beforehand: The goal was the screening of heart and vascular diseases, musculoskeletal diseases and mental disorders as comprehensively as possible; the quality control evaluation showed the sensitivity of the screening sufficient. Also a random sample of the participants of the basic health examination (every fifth) was invited to a clinical health examination. Among the additional examinations carried out the most important one was the standard medical examination which included the assessment of diagnoses, need for treatment and work and functional capacity (MS018, MS061, MS060).
MS018 Cardiovascular and respiratory diseases: physician’s examination
MS061 Musculoskeletal diseases: physician’s examination
MS060 Other diseases, functional ability, work capacity, need for care, conclusions: physician’s examination
Report on non-participants: The data concerning the health of the individuals not attending the field investigation was retrieved using a mailed questionnaire (MS066). Those in institutional treatment were contacted via a telephone call, during which the physician from the Finnish Mobile Clinic completed an interview (MS068) with the physician or nurse treating the patient. The registry data from the whole sample (also for the non-participants) has been linked to the database.
MS066 Non-participants’ questionnaire
MS068 Telephone interview for individuals in institutional care
Quality control: The quality of the data was taken care of during the different stages of the survey:
- The research conditions were standardized.
- The effect of the daily and seasonal variation was equalized over the survey data.
- The order of the study areas in the survey was planned so that the seasonal variation did not weaken the validity of the comparisons between areas.
- The measuring methods were standardized, the measurers were trained, written instructions were compiled, actions were under surveillance and the data quality was monitored.
- The significance of the difference between measurers was reduced by dividing the participants randomly to different measurers and by using different instruments alternately.
To assess the magnitude of the variation, biological and analytical repeatability was evaluated:
- biological repeatability (e.g. basic questionnaire, PSE (present state examination) interview, musculoskeletal symptom and heart and respiration symptom interviews, serum lipoprotein and urine trace element determinations) and
- analytical repeatability (e.g. coding of occupations, resting ECG strips, chest X-ray images and PSE) in subsamples
Additionally, the following actions were carried out
- reference measurements (blood pressure, spirometry, resting ECG strips and X-ray images, dual stethoscope measurement and PSE interview)
- parallel measurements (e.g. classification of occupations, PSE interview, dental examination and the clinical medical examination)
- comparison of questionnaire and interview data with the assessment of the field physician (Heliövaara et al. 1993a).
- blood pressure, spirometry and muscular power follow-up for the field staff during the whole field investigation
In the laboratory, there was a quality control with internal and external reference measurements and repeated measurements.
To assess the reliability of the screening, a clinical examination was carried out for a random sample of participants. Every fifth person from the sample was selected for the examination starting from the Äänekoski strata (Heliövaara et al. 1989, 1993a).
Outside the actual survey sample, a sample of about 600 persons in Turku was selected to a quality control trial where they were examined in the beginning and at the end of the Mini-Finland field examination and once in the middle of it. The purpose was to evaluate the changes in the phenomena of the objects of the study and measurement methods during the two-year field investigation. Special emphasis was on blood pressure, spirometry and joint function examinations, for which parallel and repeated measurements were carried out during each stage.
Finally, persons with specific diseases, symptoms or findings were selected based on predetermined criteria along with healthy controls to an advanced examination at the Social Insurance Institution’s rehabilitation center. The most essential purpose was to evaluate the validity of the clinical examination and the diagnostic assessments made in it. Only the results of about 300 persons regarding the musculoskeletal examination have been taken to the database (Heliövaara et al. 1993b).
Results of the quality control have been presented in a separate document.
