Public Health Report

Category: Childhood Development

The First 1,000 Days Define the Rest of Our Lives: New Infant Nutrition Research

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The Lancet recently published a review paper emphasizing the importance of nutrition in the first 1,000 days after birth. New scientific research is supporting this concept to a remarkable degree, with a Brigham Young University study finding that infant feeding practices predict obesity in adults. Additional studies released in the last few weeks indicate extensive health effects in formula-fed infants and increased brain development in breastfed infants.

You Are What You Ate

What you consume as an infant impacts your health for the rest of your life. According to the Lancet paper, malnutrition as a baby can have particularly lasting effects on an individual, and may be a contributing factor to the growing epidemic of metabolic diseases like diabetes.

While the consensus that breastfeeding leads to better health is not new, the mounting evidence shows that breastfeeding deserves a strong public health push. What little money is available for public health right now would be well spent on an issue that has such broad potential health benefits.

A study in Rhesus monkeys highlights the wide range of benefits of breast milk. Researchers at UC Davis found that compared to breastfed monkeys, those that were formula fed had altered gut flora as well as (possibly related) reduced function of their immune systems and metabolism.

Additionally, a Brown University brain development study employed several methods to measure brain development in infants. The researchers found that children who had been breastfed had much stronger development in some brain regions. While this is just a single study, it supports previous findings in adolescents.

The figures examining myelin water fraction, a measure of white matter growth, are particularly remarkable. By that measure, some brain regions experienced as much as 34% greater development in breastfed children as compared to formula-fed.

Science Needed

While many studies have shown long term health benefits of breastfeeding, there is still a need for more research.

Ethical considerations make true randomized studies difficult in this field. As a recent WHO review of long-term breastfeeding effects points out, the well-recognized short term benefits to infant disease and mortality make it unethical to assign a formula-only group at random. Because of this, long term effects can be obscured by the effects of parenting and environment (parents who choose to breastfeed may share other characteristics).

Additionally, the current recommendations would benefit from more information on the cause of long term benefits. Not all mothers have the option of breastfeeding, so there needs to be a better alternative.

The real story in this new research is that the development of baby formula has not progressed as well as one would hope. It is currently a poor alternative and while we may never (in the near future) be able to reproduce all of the benefits of breastfeeding, it is hard to believe that we can’t do better.

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Teen Childbearing Drops to Record Low: What Went Right?

The National Center for Health Statistics today released an analysis of teen birth rates showing a dramatic decline since 1991. As of 2011, 15-19 year-olds of all races are having children at a rate of 31.3 per 1000 women, a record low and an impressive improvement from the 61.8 level in 1991.

As shown in the graph below, the decline is particularly apparent in non-white populations.

Birth rates for teenagers aged 15–19, by race and Hispanic origin: United States, 1991, 2007, and 2011Image

Source:CDC/NCHS, National Vital Statistics System.

You may notice that the two time intervals are very different in this chart. The 20.3 women per 1000 drop from 1991-2007 represents a decline of 1.3/year, whereas the 2007-2011 fall of 10.2 women actually represents a significant acceleration at 2.6/year. This is, however, a misleading comparison. These numbers appear to have been chosen for highest dramatic effect: both 1991 and 2007 are years which occur at the apex of an atypical upward trend. While it is true that the rates have declined significantly over the years, the effect is much exaggerated by the choice of years to highlight. This is illustrated by the following Congressional Research Service chart, which gives us the whole picture:

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It is worth noting that an important ideological shift in federal sex education funding occurred in 2010. According to a report issued by the Congressional Research Service last month, the federal government underwent 3 major eras in their strategies to prevent teen pregnancy.

1981 heralded the first federal program to be tasked exclusively with adolescent issues of sexuality and pregnancy, the Adolescent Family Life program (AFL). They initiated a variety of intervention programs, encouraging contraception and abstinence strategies for avoiding pregnancies and STDs. In 1996, the Title V Abstinence Education block grant and other federal funding mechanisms began to focus on abstinence-only education strategies. The focus on abstinence-only policies continued until FY2010, when funding was provided for several evidence-based programs. This evidence-based approach included the acknowledgment that many high-schoolers (47.4% in 2011) have already experienced sexual intercourse and might not be receptive to the abstinence-only approach.

There are no doubt many factors involved in the change in teen pregnancy rate over the years, but the CRS chart does imply that the initial AFL approach was not very effective, and that we have gotten better at reaching teens with all of the messages we have chosen to use since 1991.

So which states are doing best at reducing teen pregnancy rates? First let’s look at the CDC’s heat map:

Percent change in birth rates for all teenagers aged 15–19, by state: United States, 2007 and 2011Image

Source: CDC/NCHS, National Vital Statistics System.

The states with the most significant decline in teen birth rates are Arizona and Utah, both with a 35% decline from 2007-2011. In the lower 3, West Virginia, District of Columbia, and Arkansas experienced an insignificant, 15, and 16% decline respectively (with Alaska also coming in at 16%). While North Dakota also experienced an insignificant decline, it has remained below the national average in both years examined.

Looking at the 2011 teen pregnancy rates, the highest 5 states average 301% higher than the lowest 5.  While it is hard to tell from this data what is causing the large disparities between states, the broad differences indicate that it will be worthwhile to perform analyses on a state-by-state level rather than focusing on federal policy alone.