Youths who received any breastfeeding for at least 12 months or full breastfeeding for at least six months had lower odds of developing type 1 diabetes.
Data was evaluated from two population-based cohorts on 155,392 children followed from birth (1996-2009) to 2014 (Danish National Birth Cohort) or 2015 (Norwegian Mother and Child Cohort Study) to determine the relationship between the duration of full or any breastfeeding and the risk for type 1 diabetes in children. Infant dietary practices were reported by parents when children were ages 6 and 18 months. The outcome was clinical type 1 diabetes, ascertained from nationwide childhood diabetes registries. Hazard ratios were estimated using Cox regression.
Overall, 504 participants developed type 1 diabetes for an incidence of 30.5 per 100,000 person-years in the Norwegian Mother and Child Cohort and 23.5 per 100,000 person-years in the Danish National Birth Cohort.
Children who were never breastfed had a twofold increased risk of type 1 diabetes compared with those who were breastfed (hazard ratio 2.29 [95% CI 1.14–4.61] for no breastfeeding vs. any breastfeeding for ≥12 months). Among those who were breastfed, however, the incidence of type 1 diabetes was independent of duration of both full breastfeeding (hazard ratio per month 0.99 [95% CI 0.97–1.01]) and any breastfeeding (0.97 [0.92–1.03]).
Breastfeeding was never initiated in 0.8% of the Norwegian cohort and 2.4% of the Danish cohort; full breastfeeding for at least 6 months was reported in 13.8% of the Norwegian cohort and 6.3% of the Danish cohort; any breastfeeding for at least 12 months was reported in 38.5% of the Norwegian cohort and 20.2% of the Danish cohort.
The risk for developing type 1 diabetes was higher in children who were never breastfed compared with any breastfeeding for at least 12 months (HR = 2.29; 95% CI, 1.14-4.61) and compared with full breastfeeding for at least 6 months (HR = 2.31; 95% CI, 1.11-4.8).
“The results from two of the world’s largest birth cohorts provide suggestive evidence for the hypothesis that initiating breastfeeding may reduce the risk of type 1 diabetes,” the researchers wrote. “However, among those who were breastfed, the study provides strong evidence against a clinically important association with prolonging full or any breastfeeding and risk of type 1 diabetes.
In another but similar study, Nonindigenous Canadian mothers who initiated breastfeeding in the hospital reduced their risk for diabetes by 23%, whereas their offspring experienced an 18% risk reduction for developing the disease, according to study findings presented at the World Diabetes Congress.
In this population-based analysis of more than 330,000 live births during a 24-year period, researchers also found that women saw a 14% risk reduction for diabetes when they initiated breastfeeding.
The message from these studies is that, “every mother should try to initiate breastfeeding if she can, no matter how long the duration, to receive beneficial effects … including reducing the risk for diabetes.”
For this study, they analyzed hospital records from 334,553 deliveries (60,088 First Nation births) taking place in Manitoba between 1987 and 2011. Within the cohort, 262,124 women initiated breastfeeding in the hospital (mean age, 28 years; 13% First Nations; 2.9% with gestational diabetes), and 72,429 did not initiate breastfeeding (mean age, 26 years; 36% First Nations; 4.2% with gestational diabetes), according to hospital records that note breastfeeding initiation at discharge. Researchers also determined diabetes status through hospital records.
Breastfeeding initiation was associated with significantly lower incidence of diabetes in mothers and offspring without a history of gestational diabetes.
Researchers found that First Nations status did not significantly affect the association between breastfeeding and incident diabetes for offspring and, therefore, pooled analyses, finding that children of mothers who initiated breastfeeding had an 18% reduced risk for diabetes (adjusted HR = 0.83; 95% CI, 0.69-0.99).
The protective effects of breastfeeding observed in mothers and children were independent of First Nations status, gestational diabetes, gestational hypertension, maternal age, birth weight, and socioeconomic factors, according to researchers.
- Any breastfeeding for at least 12 months or full breastfeeding for at least 6 months decreases a child’s risk for developing type 1 diabetes compared with no breastfeeding.
- No evidence indicated that prolonging full or any breastfeeding was associated with a reduced risk of type 1 diabetes.
- Breastfeeding initiation was associated with significantly lower incidence of diabetes in mothers and offspring without a history of gestational diabetes
Diabetes Care 2017 May; dc170016. https://doi.org/10.2337/dc17-0016
Martens PJ, et al. Abstract #0511. Presented at: World Diabetes Congress; Nov. 30-Dec. 4, 2015