# Calculator

## Start Calculator

## How the Calculator Works

Different durations of breastfeeding are associated with differences in health outcomes for mothers and for children. To create this cost calculator, we estimated the difference in disease burden associated with a unit-change in rates of any breastfeeding at 0 to 12 months and in exclusive breastfeeding from 0 to 6 months. Users can select the entire US, or a specific state, to see breastfeeding rates at baseline (either US rate in 2012 or 2014), and then specify "future" any breastfeeding rates of their choice at 0, 6 and 12 months, as well as exclusive breastfeeding rates at 0, 3 and 6 months. Users can hand enter the future rate, or select Healthy People 2020 goals, 80% rates at all time points, or 90% at all time points. The calculator then estimates the expected difference in disease burden.

U.S. and state-level estimates take into account each locality's number of births, very low birth weight births, mothers, and proportion of non-Hispanic black children to generate estimates.

Results are presented as estimates and 95% confidence intervals. The confidence intervals describe the range of results that we'd expect across multiple runs of our model. In some cases, the confidence intervals include a negative number. For example, for deaths from breast cancer, comparing current US breastfeeding rates to 90% rates, the estimate is 875 (-988, 2,912). That means that our best estimate if 875 deaths prevented, but it's possible that as many as 2912 deaths might be prevented, or that 988 more deaths might occur.

As with any mathematical model, there are limitations to the calculator.

The cost calculator was based on a computer model taken from the literature on the association between breastfeeding and 9 pediatric diseases and 5 maternal diseases in high income countries. The association between of breastfeeding on some of these conditions may be very different in low and middle income countries, particularly pediatric gastrointestinal infections. Our estimates also reflect the incidence of health conditions in the US, and some conditions may differ dramatically from one high income country to another. For example, rates of SIDS, are lower in Japan than in the US and the UK.

Next, incidences of the cases are determined based on demographic factors that exist in the United States, which is influenced by factors such as differential access to health care.

Finally, costs used in this calculator are based on US health care costs, which tend to be higher than in countries with universal health care.

In addition, the literature around breastfeeding and disease is continually evolving. Health outcomes that were once thought to be strongly linked with breastfeeding are now no longer thought to be, such as asthma and eczema, and other health outcomes are now thought to have a much stronger association with breastfeeding than previously appreciated, such as SIDS and necrotizing enterocolitis.

Moreover, the current model is based on the assumption that the birth rates and breastfeeding rates remain constant. If breastfeeding rates improve, and/or birth rates decrease, cost savings will be less.

I understand the following limitations and agree to the following conditions:

-These results are estimates and cannot be guaranteed.

–The calculator allows the user to enter BF rates of 100% for all time points. Users should use 100% initiation with caution because using 100% would not allow for the realization that not all mother-infant dyads can initiate breastfeeding based on the literature.^{1}

–The calculator assumes that 100% of women who did initiate breastfeeding have the potential to continue to provide at least some of their infant’s feedings through 18 months of age. The actual number of women still breastfeeding at any time point is dependent on the number of women breastfeeding at the closest preceding time point and the proportion of women that continued from the starting time point (e.g. 12 months) to the next time point (e.g. 18 months) using the user defined baseline (either US 2012 rates or US 2014 rates; the default is 2012) and rate changes over time as the referent.

–The calculator assumes that later BF rates (e.g. exclusivity at 3 months) cannot exceed earlier BF rates (e.g. exclusivity in hospital) For example: breastfeeding exclusively at 3 months cannot be 90% if breastfeeding exclusively in hospital is 80%. Further, the calculator assumes that there is a linear drop off between time points.

The research upon which the calculator was based^{2} has the following limitations:

-It is based on assumptions and results outlined in existing literature for of breastfeeding rates, disease rates, death rates, and costs. While we intend to update the calculator and the underlying model periodically, these and other assumptions could be incorrect or could change over time. Note that our research used the most conservative estimates in the literature. Note that for many of the childhood diseases, “any breastfeeding” was used as the comparator to “no breastfeeding,” not exclusive breastfeeding.

-We assumed that associations between breastfeeding and disease are causal. Note that we used risks for the published literature that controlled for multiple socio-demographic confounders.

-The research assumes a steady state over the lifetime of the modeled cohort that forms the basis of the calculator: that population size, fertility rates, disease rates, mortality rates, and breastfeeding rates do not change.

-Use of US costs may limit the generalizability of this calculator to other countries.

-The selection of appropriate costs for the loss of human life is controversial.

**Please cite all results obtained from the calculator as follows:**

Breastfeeding Saves Lives Calculator, www.usbreastfeeding.org/saving-calc, Access date and year.

Stuebe, A. M. et al (in press - 2017). An online Calculator to estimate the impact of changes in breastfeeding rates on population health and costs. *Breastfeeding Medicine*

## References:

- Stuebe AM, Horton BJ, Chetwynd E, Watkins S, Grewen K, Meltzer-Brody S. Prevalence and risk factors for early, undesired weaning attributed to lactation dysfunction.
*J Womens Health (Larchmt).*2014;23(5):404-412. - Bartick MC, Schwarz EB, Green BD, et al. Suboptimal breastfeeding in the United States: Maternal and pediatric health outcomes and costs.
*Matern Child Nutr.*2016.