Osteopontin Levels in Human Milk Vary Across Countries and Within Lactation Period: Data From a Multicenter Study.

OBJECTIVES: Osteopontin (OPN) is a multifunctional protein expressed in many cell types, tissues and body fluids with the highest concentrations found in milk; significantly higher in human than in bovine milk. Intervention studies have indicated beneficial effects of supplementing infant formula with bovine OPN. In this multicenter study, we determined the OPN content in human milk samples from 629 Chinese, Danish, Japanese and Korean mothers. METHODS: At each study site, milk samples were collected and analyzed for OPN and protein concentration using ELISA and infrared spectroscopy, respectively. RESULTS: A total of 829 milk samples from 629 women were included. When delivering the first sample, mean maternal age was 31.4 years (SD 4.0), and median infant age was 13.4 weeks (interquartile range 4.6-17.9). The median OPN concentration varied across sites; from 99.7 mg/L in Danish, 185.0 mg/L in Japanese, 216.2 mg/L in Korean to 266.2 mg/L in Chinese mothers (P < 0.001), corresponding to 1.3%, 2.4%, 1.8% and 2.7% of the total protein content (OPN/protein%) (P < 0.05), respectively. Based on 75 Chinese and 33 Japanese mothers delivering more than 1 sample, multilevel (mixed model) linear regression analysis showed a decrease in OPN concentration with infant age (ß = (-11.3), 95% confidence interval (CI) = (-13.9) to (-8.8) and ß = (-2.1), 95% CI = (-3.2) to (-0.9), respectively). CONCLUSIONS: In this large multicenter study, we observed statistically significant differences in the OPN concentration and the OPN/protein% in human milk samples between countries. Based on mothers delivering more than 1 sample, a significant decrease within the lactation period was observed.

Dietary Patterns Associated with General Health of Breastfeeding Women 1-2 Months Postpartum: Data from the Japanese Human Milk Study Cohort.

Background: The effects of dietary patterns on health outcome of lactating women remain unclear. Objectives: To describe the dietary patterns of lactating Japanese women and explore the association between dietary patterns and their general health. Methods: This study included 1096 lactating women from the Japanese Human Milk Study Cohort. The maternal diet during lactation 1-2 mo postpartum was determined using a FFQ. Dietary patterns were identified using a factor analysis based on the energy-adjusted intake of 42 food items. Trend associations between maternal and infant variables and quartiles of dietary pattern scores were tested, and logistic regression was performed to estimate the OR and 95% CI of maternal self-reporting anemia, constipation, rough skin, sensitivity to cold, and mastitis. Results: Four dietary patterns were identified in this study. The versatile vegetable diet, characterized by a high intake of vegetables, mushrooms, seaweeds, and tofu, was associated with maternal age, BMI prepregnancy and during the lactation periods, education, household income, and anemia. The plain Japanese diet contained a high intake of typical Japanese foods such as rice and miso soup and a low intake of bread and some confectioneries and was associated with maternal BMI during both periods. The salad vegetable diet, characterized by a high intake of raw vegetables and tomatoes with mayonnaise or dressing, was associated with parity and season in which data collection was conducted. The seafood diet, characterized by a high intake of fish, squid, octopus, shrimp, and shellfish, was associated with days postpartum and sensitivity to cold. Conclusions: Four dietary patterns were identified and were independently associated with socioeconomic factors. The versatile vegetables diet and seafood diet were associated with anemia and sensitivity to cold, respectively, among the participants. This trial was registered at the Japanese Clinical Trials Registry (https://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000017649) as UMIN000015494.

Relationship between Child Care Exhaustion and Breastfeeding Type at Two and Six Months in a Cohort of 1210 Japanese Mothers.

This study investigated whether parenting stress is associated with breastfeeding type (exclusive or partial). Between 2014 and 2019, we recruited 1210 healthy mothers (mean age, 31.2 years; 65%, multiparity) from 73 obstetric institutions across all prefectures of Japan. Among these, 1120 mothers at two months and 1035 mothers at six months were investigated for parenting stress and breastfeeding type: exclusive versus otherwise (partial). Parenting stress was measured by a validated Japanese scale consisting of childcare exhaustion, worry about child's development, and no partner support. Exclusive breastfeeding prevalence was 75% at two and 78% at six months. The total scores for childcare exhaustion and worry about child development were statistically higher in the partial breastfeeding group than in the exclusive breastfeeding group at two months but not at six months. A logistic regression model demonstrated that childcare exhaustion was significantly associated with an increased risk of having partial breastfeeding at two months after adjusting for the maternal Body Mass Index, parity, and baby's current weight. However, the association was no longer significant at six months. The present study suggests that intervention for parenting stress at two months postpartum may promote prolonged exclusive breastfeeding.

Cohort profile: Japanese human milk study, a prospective birth cohort: baseline data for lactating women, infants and human milk macronutrients.

PURPOSE: The Japanese Human Milk Study, a longitudinal prospective cohort study, was set up to clarify how maternal health, nutritional status, lifestyle and sociodemographic and economic factors affect breastfeeding practices and human milk composition. This would eventually determine factors affecting the growth and development of infants and children. PARTICIPANTS: A total of 1210 Japanese lactating women who satisfied the inclusion criteria, were invited across the country at various participating sites, between 2014 and 2019. Finally a total of 1122 women were enrolled in this study. FINDINGS TO DATE: Among 1122 eligible participants, mean age at delivery was 31.2 (SD 4.4) years and mean prepregnancy BMI was 20.8 (SD 2.7). Among these women, 35% were previously nulliparous and 77.7% had college, university or higher education. The mean gestational period was 39.0 (SD 1.3) weeks. Caesarean section was reported among 11.9%; mean infant birth weight was 3082 (SD 360) g. Of the infants, 53.7% were male. Overall, our participants appeared to be healthier than the general population in Japan. Analyses of the 1079 eligible human milk samples obtained at the first and second months postpartum showed the following composition: carbohydrate, 8.13 (SD 0.32) g/100 mL; fat, 3.77 (SD 1.29) g/100 mL; and crude protein, 1.20 (SD 0.23) g/100 mL. We also analysed osteopontin, fatty acid, vitamin D and phospholipid levels in limited subcohorts of the samples. FUTURE PLANS: Follow-up surveys will be conducted to obtain milk samples every 2 months for 12 months and to investigate mother and child health until the children reach 5 years of age. These will be completed in 2024. We plan to longitudinally analyse the composition of macronutrients and various bioactive factors in human milk and investigate the lifestyle and environmental factors that influence breastfeeding practices, maternal and child health, and child development. TRIAL REGISTRATION NUMBER: UMIN000015494; pre-results.

Maternal Health and Nutrition Status, Human Milk Composition, and Growth and Development of Infants and Children: A Prospective Japanese Human Milk Study Protocol.

It is unknown whether maternal health and nutrition are related to human milk composition or growth and development of infants and children. Here, we describe a protocol for a prospective five-year cohort study to clarify (i) how maternal health and nutrition, socioeconomic factors, and lifestyles affect human milk composition, and (ii) whether these are associated with growth and development of infants and children. In our study, we recruited 1210 Japanese mothers with singleton pregnancies from 73 obstetrics clinics and hospitals across Japan, between 2014 and 2019. We will measure the following: health information regarding maternal-child dyads using a self-administered questionnaire, maternal nutrition during breastfeeding using a Brief self-administrated Diet History Questionnaire, the development of infants and children using the Kinder Infant Development Scale, and the stress related to child rearing using the Mother's Child Care Stress Scale. Simultaneously, we will collect human milk every 2 months during the first year after birth to measure its composition and levels of macronutrients. This study will generate useful data to investigate whether health status, nutritional status, lifestyle, and socioeconomic factors affect human milk composition and the growth and development of infants and children.