Background: There is limited evidence about diet quality and associated factors in a representative population-based sample of preschool-aged children in Finland.

Objective: The aims of this study were to investigate (1) the extent to which child diet quality and the consumption of health indicator foods (vegetables, fruits, berries, vegetable oil-based spread, nonfat milk) are in accordance with Finnish recommendations for preschool-aged children, (2) whether diet quality differs between children with underweight or normal weight compared with children with overweight or obesity, and (3) whether parental or child factors are related to children's diet quality.

Design: This was a cross-sectional study.

Participants/setting: Healthy children aged 2 to 6 years (n = 766) were recruited from child health clinics across Finland from February to June 2016.

Main outcome measures: Diet quality and consumption of the health indicator foods were assessed by the Children's Index of Diet Quality (CIDQ, score 0-21, values < 10 indicate poor; 10-13.5, moderate; and ≥14, good diet quality). Parental information was collected with a self-administered questionnaire. Child weight and height were measured by child health clinic nurses.

Statistical analyses: The overweight/obesity status and diet quality of the children were compared with 1-way analysis of variance. One-way analysis of variance was used as the preliminary analysis between child and parental factors and CIDQ scores, and linear mixed model analysis to further analyze the relationship between child and parental factors and CIDQ data.

Results: Only a small minority (13.7%) of the children had a good diet quality, 55.4% had a moderate diet quality, and 30.9% had a poor diet quality. Only 1% of the children consumed the key health indicator foods, namely vegetables, fruits, and berries, as recommended. Diet quality did not differ between children with underweight/normal weight and overweight/obesity. Instead, the child's younger age, parents' higher education, and parents' self-perceived healthy diet were related to good diet quality in the child.

Conclusions: The diet quality was moderate or poor in the majority of the children. Parental characteristics were the main factors related to the child's diet quality. The results suggest that future efforts to improve preschool-aged children's diet quality are needed including efforts to counsel families in pediatric care. Whether the findings from the current study also apply to Finnish school-aged children should be investigated further.