Vitamin B12 status in infancy and the effect of a vitamin B12 injection in infants with subclinical vitamin B12 deficiency: study protocol for a register-based randomised controlled trial.

INTRODUCTION: Vitamin B12 (cobalamin) is crucial for optimal child development and growth, yet deficiency is common worldwide. The aim of this study is twofold; (1) to describe vitamin B12 status and the status of other micronutrients in Norwegian infants, and (2) in a randomised controlled trial (RCT), investigate the effect of vitamin B12 supplementation on neurodevelopment in infants with subclinical vitamin B12 deficiency. METHODS AND ANALYSIS: Infant blood samples, collected at public healthcare clinics, are analysed for plasma cobalamin levels. Infants with plasma cobalamin <148 pmol/L are immediately treated with hydroxocobalamin and excluded from the RCT. Remaining infants (cobalamin ≥148 pmol/L) are randomly assigned (in a 1:1 ratio) to either a screening or a control group. In the screening group, baseline samples are immediately analysed for total homocysteine (tHcy), while in the control group, the baseline samples will be analysed after 12 months. Screening group infants with plasma tHcy >6.5 µmol/L, are given an intramuscular injection of hydroxocobalamin (400 µg). The primary outcomes are cognitive, language and motor development assessed using the Bayley Scales of Infant and Toddler Development at 12 months of age. ETHICS AND DISSEMINATION: The study has been approved by the Regional Committee for Medical and Health Research Ethics (ref: 186505). Investigators who meet the Vancouver requirements will be eligible for authorship and be responsible for dissemination of study findings. Results will extend current knowledge on consequences of subclinical vitamin B12 deficiency during infancy and may inform future infant feeding recommendations. TRIAL REGISTRATION NUMBER: NCT05005897.

Adequate Urinary Iodine Concentration among Infants in the Inland Area of Norway.

Considering the importance of iodine to support optimal growth and neurological development of the brain and central nervous system, this study aimed to assess and evaluate iodine status in Norwegian infants. We collected data on dietary intake of iodine, iodine knowledge in mothers, and assessed iodine concentration in mother's breast milk and in infant's urine in a cross-sectional study at two public healthcare clinics in the inland area of Norway. In the 130 mother-infant pairs, the estimated infant 24-h median iodine intake was 50 (IQR 31, 78) µg/day. The median infant urinary iodine concentration (UIC) was 146 (IQR 93, 250) µg/L and within the recommended median defined by the World Health Organization for this age group. Weaned infants had a higher UIC [210 (IQR 130, 330) µg/L] than exclusively breastfed infants [130 (IQR 78, 210) µg/L] and partially breastfed infants [135 (IQR 89, 250) µg/L], which suggest that the dietary data obtained in this study did not capture the accurate iodine intake of the included infants. The iodine status of infants in the inland area of Norway seemed adequate. Weaned infants had higher UIC compared to breastfed infants, suggesting early access and consumption of other sources of iodine in addition to breast milk.

Mild to Moderate Iodine Deficiency and Inadequate Iodine Intake in Lactating Women in the Inland Area of Norway.

Breastfed infants are dependent on an adequate supply of iodine in human milk for the production of thyroid hormones, necessary for development of the brain. Despite the importance of iodine for infant health, data on Norwegian lactating women are scarce. We measured iodine intake and evaluated iodine status and iodine knowledge among lactating women. From October to December 2018, 133 mother-infant pairs were recruited in a cross-sectional study through two public health care centers in Lillehammer and Gjøvik. Each of the women provided two human milk specimens, which were pooled, and one urine sample for analysis of iodine concentration. We used 24-hour dietary recall and food frequency questionnaire (FFQ) to estimate short-term and habitual iodine intake from food and supplements. The median (P25, P75) human milk iodine concentration (HMIC) was 71 (45, 127) µg/L-of which, 66% had HMIC <100 µg/L. The median (P25, P75) urinary iodine concentration (UIC) was 80 µg/L (52, 141). The mean (± SD) 24-hour iodine intake and habitual intake was 78 ± 79 µg/day and 75 ± 73 µg/day, respectively. In conclusion, this study confirms inadequate iodine intake and insufficient iodine status among lactating women in the inland area of Norway and medium knowledge awareness about iodine.