Relative validity of a web-based food frequency questionnaire for Danish adolescents.

BACKGROUND: With increased focus on dietary intake among youth and risk of diseases later in life, it is of importance, prior to assessing diet-disease relationships, to examine the validity of the dietary assessment tool. This study's objective was to evaluate the relative validity of a self-administered web-based FFQ among Danish children aged 12 to 15 years. METHODS: From a nested sub-cohort within the Danish National Birth Cohort, 124 adolescents participated. Four weeks after completion of the FFQ, adolescents were invited to complete three telephone-based 24HRs; administered 4 weeks apart. Mean or median intakes of nutrients and food groups estimated from the FFQ were compared with the mean of 3x24HRs. To assess the level of ranking we calculated the proportion of correctly classified into the same quartile, and the proportion of misclassified (into the opposite quartile). Spearman's correlation coefficients and de-attenuated coefficients were calculated to assess agreement between the FFQ and 24HRs. RESULTS: The mean percentage of all food groups, for adolescents classified into the same and opposite quartile was 35 and 7.5%, respectively. Mean Spearman's correlation was 0.28 for food groups and 0.35 for nutrients, respectively. Adjustment for energy and within-person variation in the 24HRs had little effect on the magnitude of the correlations for food groups and nutrients. We found overestimation by the FFQ compared with the 24HRs for fish, fruits, vegetables, oils and dressing and underestimation by the FFQ for meat/poultry and sweets. Median intake of beverages, dairy, bread, cereals, the mean total energy and carbohydrate intake did not differ significantly between the two methods. CONCLUSION: The relative validity of the FFQ compared with the 3x24HRs showed that the ranking ability differed across food groups and nutrients with best ranking for estimated intake of dairy, fruits, and oils and dressing. Larger variation was observed for fish, sweets and vegetables. For nutrients, the ranking ability was acceptable for fatty acids and iron. When evaluating estimates from the FFQ among Danish adolescents these findings should be considered.

Increased leptin, decreased adiponectin and FGF21 concentrations in adolescent offspring of women with gestational diabetes.

OBJECTIVE: Fetal exposure to gestational diabetes mellitus (GDM) increases the risk of metabolic diseases in the offspring. Leptin, adiponectin, and fibroblast growth factor 21 (FGF21) may play potential roles in the underlying disease mechanisms. We investigated the impact of fetal exposure to GDM on leptin, adiponectin, and FGF21 concentrations and their associations with measures of adiposity and metabolic traits during childhood/adolescence. DESIGN AND METHODS: The follow-up study included 504 GDM and 540 control offspring aged 9-16 from the Danish National Birth Cohort. Anthropometric measurements, fasting blood samples, puberty status and fat percentages by dual-energy X-ray absorptiometry were examined. Serum concentrations of leptin, adiponectin, and FGF21 were measured by validated immune assays. RESULTS: GDM offspring had 38% (95% CI: 22-55%) higher leptin, 0.6 mg/L (95% CI: -1.2, -0.04 mg/L) lower adiponectin, and 32% (95% CI: -47%, -12%) lower FGF21 concentrations than control offspring (P < 0.05). After adjustment for confounders including maternal pre-pregnancy BMI, GDM offspring had borderline higher leptin (P = 0.06) and significantly lower FGF21 concentrations (P = 0.006). When accounting for offspring BMI z-score, GDM exposure had no significant independent effect on leptin or adiponectin concentrations, whereas FGF21 was still significant. In univariate analyses, leptin and adiponectin were associated with fasting insulin, HOMA-IR, and adiposity, and FGF21 with total fat percentage. CONCLUSIONS: GDM offspring had higher leptin, lower adiponectin and FGF21 concentrations than control offspring. Elevated leptin and decreased adiponectin concentrations associated with adverse metabolic traits and were most likely driven by higher obesity prevalence among GDM offspring. The functional implications of decreased FGF21 concentrations among GDM offspring need to be further explored.

Adiposity, Dysmetabolic Traits, and Earlier Onset of Female Puberty in Adolescent Offspring of Women With Gestational Diabetes Mellitus: A Clinical Study Within the Danish National Birth Cohort.

OBJECTIVE: Offspring of pregnancies affected by gestational diabetes mellitus (GDM) are at increased risk of the development of type 2 diabetes. However, the extent to which these dysmetabolic traits may be due to offspring and/or maternal adiposity is unknown. We examined body composition and associated cardiometabolic traits in 561 9- to 16-year-old offspring of mothers with GDM and 597 control offspring. RESEARCH DESIGN AND METHODS: We measured anthropometric characteristics; puberty status; blood pressure; and fasting glucose, insulin, C-peptide, and lipid levels; and conducted a DEXA scan in a subset of the cohort. Differences in the outcomes between offspring of mothers with GDM and control subjects were examined using linear and logistic regression models. RESULTS: After adjustment for age and sex, offspring of mothers with GDM displayed higher weight, BMI, waist-to-hip ratio (WHR), systolic blood pressure, and resting heart rate and lower height. Offspring of mothers with GDM had higher total and abdominal fat percentages and lower muscle mass percentages, but these differences disappeared after correction for offspring BMI. The offspring of mothers with GDM displayed higher fasting plasma glucose, insulin, C-peptide, HOMA-insulin resistance (IR), and plasma triglyceride levels, whereas fasting plasma HDL cholesterol levels were decreased. Female offspring of mothers with GDM had an earlier onset of puberty than control offspring. Offspring of mothers with GDM had significantly higher BMI, WHR, fasting glucose, and HOMA-IR levels after adjustment for maternal prepregnancy BMI, and glucose and HOMA-IR remained elevated in the offspring of mothers with GDM after correction for both maternal and offspring BMIs. CONCLUSIONS: In summary, adolescent offspring of women with GDM show increased adiposity, an adverse cardiometabolic profile, and earlier onset of puberty among girls. Increased fasting glucose and HOMA-IR levels among the offspring of mothers with GDM may be explained by the programming effects of hyperglycemia in pregnancy.