Variable | Time frame | Database | Operation definition/ICD codes |
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Mother's age at birth of index child | Year of birth of index child | Registry | A woman’s age at birth of index child was determined by subtracting the date of conception of the index child by the birth date of the mother |
History of a teen birth or pregnancy | 15 years prior to the birth of the index child | Hospital Abstracts | A woman was identified has having a history of teen pregnancy or birth if they had the following diagnostic codes from the ages 15–19:
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Region of residence—urban/rural | Year of birth of index child | Registry | Region of residence is categorised as being rural or urban as determined by the postal code registered with Manitoba Health. Those who are registered to Winnipeg (population=xxx) or Brandon (population=yyy) are categorised as urban, while the rest of Manitoba is considered to be rural |
Region of residence—RHA | Year of birth of index child | Registry | In Manitoba, an RHA is a regional governance structure set up by the provincial government to be responsible for the delivery and administration of health services in a specified geographic area. From July 2002 to 2 June 2012 Manitoba consisted for the following RHAs: Winnipeg, Brandon, South Eastman, Assiniboine, Central, Parkland, North Eastman, Interlake, Burntwood, NOR-MAN, and Churchill. On 1 June 2012 these existing 11 RHAs were amalgamated into five larger regions. The new RHAs are listed below, with the old RHAs listed in brackets:
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Income Quintiles | Five years prior to the birth of the index child | Registry: Census Data | Income quintile is an aggregate, area-level measure of the average household income of residents in small areas, ranking them from poorest to wealthiest, and then grouping the population into five equal categories (1 being the poorest and 5 being the wealthiest). Each quintile contains ∼20% of the population. The income quintile measure is derived from the 2006 Statistics Canada Census data by aggregating household income to the dissemination area and then ranking neighbourhoods by income. Income quintiles are produced separately for urban and rural populations and are used as a proxy measure of individual SES. If the postal code is missing for a study participant, income quintiles cannot be calculated |
Receipt of income assistance | 5 years prior to the birth of the index child | Registry: Social Assistance | A woman was identified as having received income assistance if she was coded as having received income assistance from the social assistance management information database anytime during the period of 5 years before the birth of the child |
SES | Year of birth of index child | Registry: Census Data | SES was defined according to income quintiles and income assistance data. A woman was considered to have:
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Maternal education level—high school completion | Education: enrolment, marks and assessment data | A woman was considered to have completed high school if she graduated within 6 years of starting grade nine. Criteria to assess if she graduated includes:
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Involvement with the Justice System | During the entire study period | Manitoba Justice | A woman was considered to have involvement with the justices system if she had a record of an incident in the Prosecutions Information Management System. Involvement type was classified by the following categories: (1) witness; (2) victim; (3) accused |
RHA, Regional Health Authority; SES, socioeconomic status.