Lecture: "Ecological life-course Epidemiology": Professor and Special Physician Anne Hammarström at the Dep. of Public Health and Caring Sciences

  • Date: 10/31/2017 at 2:15 PM 4:00 PM
  • Location: Biomedicinskt centrum, BMC C2:301
  • Lecturer: Professor and Special Physician Anne Hammarström at the Dep. of Public Health and Caring Sciences
  • Website
  • Organizer: Dep. of Pharmaceutical Sciences, Pharmacometrics
  • Contact person: Ulrika Simonsson
  • Phone: 018-471 46 85
  • Föreläsning

Professor and Special Physician Anne Hammarström at the Dep. of Public Health and Caring Sciences: "Ecological life-course Epidemiology"

Background to the study

As a young specialist physician in social medicine in Sweden at the end of 1970 I (Anne Hammarström) was interested in studying the importance of important societal problems for people’s health. At that time, the levels of youth unemployment were high. Besides, I met unemployed patients with lots of different health problems. I considered youth unemployment to be one of the most serious societal problems and found almost no research of its possible health consequences. While some studies were available about the health consequences of unemployment in the adult population1-3, there was a lack of research about possible health consequences of youth unemployment. Thus, I and Urban Janlert decided to perform a longitudinal study of a cohort of school leavers. The chosen setting was Northern Sweden, as the highest levels of both youth and adult unemployment were found in that part of Sweden. In fact, unemployment had been endemic in this part of Sweden for a long time. The county capital of Norrbotten – Luleå – was chosen as this is a typical middle-sized, industrial town which was comparable to Sweden as a whole with regard to important socio-demographic background data such as labour market structure, percentage of foreign-born, housing, divorce rate and socioeconomic status.

Population

The population consists of all 1083 pupils (506 girls and 577 boys) who attended or should have attended the last year of compulsory school in the municipality of Luleå in 1981. Extensive work was carried out to reach every participant, including those who had moved, in order to keep the non-response rate to a minimum and thus the attrition rate has been extremely low. At the 27-year follow-up 94.3% (n =1010) of those still alive (n=1071) of the original cohort continued to participate.
A subsample was made from the cohort, consisting of all participants who were in open unemployment directly after compulsory school (n=13 girls, 15 boys). They all agreed to be part of the study.
All school nurses (n=8) and form teachers (n=65) in 1981 as well as all form teachers in 1983 were also part of the sample. None refused to participate.

Design and Procedure

The cohort has been investigated in 1981, 1983, 1986, 1995 and 2008 with a comprehensive questionnaire. The two first investigations were performed at school, during school hours. For each of the other follow-ups, the participants were invited to reunions with their former classmates from compulsory school. Thus, the participants were able to answer the questionnaire under pleasant circumstances. They also received information from the project leader about the study and could ask her if they had any questions in relation to the questionnaire. The questionnaire was mailed together with a stamped, addressed envelope to those who could not attend the class meetings. A reminder was sent to all those who did not answer the first questionnaire. Personal or telephone interviews were performed with the risk group as well as with participants with difficulties in reading and writing. Then the project leader read the question and response categories exactly as written in the mailed questionnaire.

The questionnaire consisted of around 90 validated questions regarding social background, work situation, health, family situation, leisure time etc. The questionnaire was almost identical at all investigations.

Personal interviews were conducted by the PI with all form teachers and nurses for each individual pupil. The interviewed teachers had been responsible for the class during the last three last years of compulsory school. The interviews were performed in a quiet room during school time. The teacher was interviewed with a previously validated questionnaire consisting of 35 questions regarding the pupils’ situation at school. The school nurses were interviewed about the health situation of the pupils.

Measurements and register data

Blood pressure was measured at age 16, 21 and 43 and information on body mass index is available from age 16 (from the school health records), 43 (measured), 21 and 30 (self-reported). The most recent survey at age 43 also comprised a health examination including measurement of waist circumference, and blood sampling after one night’s fast were assessed for total cholesterol, HDL and LDL cholesterol, triglycerides, apolipoprotein A1 and B, fasting glucose and C-reactive protein. The participants also completed a one-day saliva collection (four samples) assessed for salivary cortisol. One blood sample was also stored at the biobank at Umeå University Hospital.

The following register data has been added to the cohort:

1.    Manual record of birth data from participants own birth: height, weight, physical status, malformation, gestational age; data regarding the mother: age, parity, diseases, complications during delivery.

2.    Manual record of school, class and (in upper secondary school) also study programme, based on information from each school.

3.    Manual record of grades (for each subject from the last year of compulsory school) based on information from the local municipality

4.    Manual record of school health data: Measurement of vision, sense of colour, hearing, weight, height, number and diagnosis of visits to the school physician (during the last three years of compulsory school), referrals (instance and diagnosis).

5.    The following data have been added from the longitudinal integration database for health insurance and labour market studies (Swedish acronym LISA) at Statistics Sweden for each year between 1992 and 2007: employment, number of employees at one’s workplace, number of sources of income, number of days (gross, net) per year in allowances due to parental leave, temporary parental leave (due to care of sick children), sick-leave, rehabilitation, work injury, preventive sick leave, unemployment and labour market measures (and which type of measures).

6.    The following data have been added from the National Social Insurance Office for 1982, 1983, 1985 – annual information about civil status, number of days in parental leave (all data missing for 1984, 1986, 1987). For 1988–1992 the following data have been added: Annual information about civil status, number of days in parental leave, extent (whole, 25%, 50%) for the participant as well as the other parent. For 1988–1992 annual information about the number of days’ sick-leave and extent (whole, 25%, 50%) has also been added.

7.    The following data have been added from the longitudinal integration database for health insurance and labour market studies (Swedish acronym LISA) at Statistics Sweden for each cohort participant as well as for all other employees at their workplaces (from 2003 until 2007): sex, age, income, education, type of workplace, number of days (gross, net) per year in allowances due to parental leave, temporary parental leave (due to care of sick children), sick-leave, rehabilitation, work injury and preventive sick leave.

The study has been approved by the Regional Ethics Vetting Board in Umeå.