19– 22 These studies examined cardiovascular outcomes in large population based groups.
This study found that children with a head injury before age 2 were twice as likely to be diagnosed as having ADHD as a population based comparison group but not more likely to be diagnosed as having ADHD than another medically attended injury group (burn injury).
The present study has no age and sex matched population based control group.
A population based comparison group (n = 153) was created and interviewed face-to-face.
Further, proportion reporting intake of a supplement the latest two weeks in early pregnant women and a population based referent group.
The HRQoL of child and adolescent retinoblastoma survivors were found to be higher on Autonomy subscales compared to the population based reference group of the country in the Netherlands [ 43].
This study found lower parent-reported HRQoL in children diagnosed through screening at age 2 4 years, but only among the children with gastrointestinal symptoms; children without symptoms had similar HRQoL as a population based reference group [ 36].
A larger cohort or perhaps longer follow up such as we have now may be necessary to characterize rates of treatment related MDS/AML using a population based comparison group [ 5].
Our study group could be considered a primary health care population and not a hospital based group [ 42].
