Swedish references for weight, weight-for-height and body mass index: The GrowUp 1990 Gothenburg study

Aim To update the Swedish references for weight, weight-for-height and body mass index (BMI) considering the secular trend for height but not including that for weight. Methods Longitudinal measures of height and weight were obtained (0-18 years) from 1418 (698 girls) healthy children from the GrowUp 1990 Gothenburg cohort born at term to non-smoking mothers and Nordic parents. A total of 145 individuals with extreme BMI value vs GrowUp 1974 BMI SDS reference were excluded (0-2 years: +/- 4SDS, 2 < years: -3SDS, +2.3SDS). References were constructed using the LMS method. Results The updated weight reference became similar to the GrowUp 1974 Gothenburg reference: BMI increased rapidly up to lower levels in the 1990 cohort during infancy/early childhood, similar in both groups in late childhood/adolescence, despite lower values at +2SDS. Compared with the WHO weight standard, median and -2SDS weight values were higher for the 1990 cohort, whereas +2SDS values were lower, resulting in narrower normal range. Median values were greater and +/- 2SDS narrower for the 1990 vs the WHO weight-for-height reference. International Obesity Task force (IOTF) BMI lines for definitions for over- and underweight were added. Conclusion We present updated references for weight, weight-for-height and BMI, providing a healthy goal for weight development when monitoring growth within healthcare settings.