Cohorts of offshore workers

The Cancer Registry has established two cohorts for offshore workers containing information about people who have worked at Norwegian oil platforms from 1965 to until today.
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The Offshore-cohort

NOPW cohort

The cohort is also called the NOPW-cohort, which is an abbreviation of «Norwegian Offshore Petroleum Workers»

Data collection: Through questionnaires delivered to individual who were believed to have worked offshore in the period 1965-1998. The survey was conducted in 1998.

Number: 28 000 offshore workers

Period: 1965-1998

Type of data: The data were self-reported through questionnaires. The questionnaire included questions about occupational history, socioeconomic conditions (marital status, education, children), lifestyle (diet, tobacco, alcohol, physical activity) and working environment factors such as exposure to fiber, dust and chemicals.

Related project: «Exposure-related risks of cancer in petroleum workers» 


A detailed description of the Offshore cohort's background and procedure for establishing the cohort can be found in the Norwegian Cancer Registry's research report nr. 1, 2001 (in Norwegian) «Kartlegging av kreftrisiko og årsakspesifikk dødelighet blant ansatte i norsk offshorevirksomhet - Innsamling av bakgrunnsdata og etablering av kohort». 


The Heliport-cohort

The cohort is based on the records of helicopter transport to and from the oilplatforms, and is therefore called the heliport cohort.

Data collection: From nine included operator companies, the Norwegian Cancer Registry has received an overview of all offshoreworkers who have been offshore since 1980. In addition we are conducting a survey, that is send directly to the offshore workers.

Number: about 83 000

Period of occupational activity for this cohort: 1980–2020

Type of data: Personal data (company, name, national identity number, telephone, education, position, job category), transport data (position, role, purpose, travel number, exit/entry, and length of stay on offshore installation, shift plan, status of stay), occupational history (position number, position, start and end of position, whether they work offshore and have shift work) and lifestyle factors (diet, physical activity, sun exposure, sleep, alcohol, tobacco).

Related projects: «Benzene-related risk of cancer among offshore workers» and «Exposure assessment and prevention of death, disease and injuries among offshoreworkers»