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MICH-21.3 Data Details

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MICH-21.3 Increase the proportion of infants who are breastfed at 1 year

About the Data: National

Description of the data source, numerator, denominator, survey questions, and other relevant details about the national estimate.

Data Source: 
National Immunization Survey
Changed Since the Healthy People 2020 Launch: 
Yes
Measure: 
percent
Baseline (Year): 
24.6 (2009)
Target: 
34.1
Target-Setting Method: 
Projection/trend analysis
Target-Setting Method Justification: 
The trend for the proportion of infants’ breastfeeding at 1 year for each year of births from 1999 through 2006 predicts an increase of 1.11 percentage points per year. The proposed target of 34.1 percent is reasonable given this trend.
Numerator: 

Number of caregivers of children born in a cohort year who indicate their child was breastfed any amount at 1 year of age

Denominator: 

Number of children aged 19-35 months born in the same cohort year

Comparable Healthy People 2010 Objective: 
Retained from HP2010 objective
Questions Used to Obtain the National Baseline Data: 

    From the 2011 through 2012 National Immunization Surveys:

    [NUMERATOR:]

    Was [child] ever breastfed or fed breast milk?

    1. Yes
    2. No

    How old was [child's name] when (he/she) completely stopped breastfeeding or being fed breast milk?

    1. ≥1 year
    2. Still breastfeeding
Data Collection Frequency: 
Annual
Methodology Notes: 

    Using a computer-generated list, the National Immunization Survey (NIS) identifies households across the United States with children aged 19–35 months and interviews the person who is most knowledgeable about the child’s immunization status (“caregiver”). Survey years are combined to calculate breastfeeding statistics by year of child’s birth (cohort) instead of the year in which the participant was surveyed. To calculate breastfeeding indicators by year of child birth, data are combined across all relevant survey years. Because children are 19—35 months of age at the time of the parent interview, each survey year represents children born over two years. For example, breastfeeding data for children in the 2009 birth cohort are obtained from NIS 2011 and 2012.

    In 2011, a cellular telephone sample of respondents was included in the National Immunization Survey (NIS) along with the landline telephone sampling frame used for all previous survey years (referred to as dual-frame sampling).In 2018, the NIS sampling frame was changed to include only a cell phone sample (referred to as single cell-frame sampling). While the inclusion of cell phones resulted in the need to revise the baselines and targets of many HP2020 objectives, the change from dual frame to single cell-frame sampling of respondents had a minimal effect on national estimates of all 6 breastfeeding indicators examined (ever breastfed, breastfed at 6 and 12 months, exclusive breastfeeding through 3 and 6 months, and formula supplementation before 2 days among breastfed infants); national prevalence estimates differed by 0.2 percentage points or less.

    The following webpage outlines all of the changes that were made to the NIS in 2011 and 2018.
    https://www.cdc.gov/breastfeeding/data/nis_data/methods.html.

About the Data: State

Description of the data source, numerator, denominator, survey questions, and other relevant details about the state-level data.

Data Source: 
National Immunization Survey
Measure: 
percent
Numerator: 

Number of caregivers of children born in a cohort year who indicate their child was breastfed any amount at 1 year of age

Denominator: 

Number of children aged 19-35 months born in the same cohort year

Questions Used to Obtain the State Data: 

      From the 2011 through 2012 National Immunization Surveys:

      [NUMERATOR:]

      Was [child] ever breastfed or fed breast milk?

      1. Yes
      2. No

      How old was [child's name] when (he/she) completely stopped breastfeeding or being fed breast milk?

      1. ≥1 year
      2. Still breastfeeding
Data Collection Frequency: 
Annual
Methodology Notes: 

      Using a computer-generated list, the National Immunization Survey (NIS) identifies households across the United States with children aged 19–35 months and interviews the person who is most knowledgeable about the child’s immunization status (“caregiver”). Survey years are combined to calculate breastfeeding statistics by year of child’s birth (cohort) instead of the year in which the participant was surveyed. To calculate breastfeeding indicators by year of child birth, data are combined across all relevant survey years. Because children are 19—35 months of age at the time of the parent interview, each survey year represents children born over two years. For example, breastfeeding data for children in the 2009 birth cohort are obtained from NIS 2011 and 2012.

      In 2011, a cellular telephone sample of respondents was included in the National Immunization Survey (NIS) along with the landline telephone sampling frame used for all previous survey years (referred to as dual-frame sampling).In 2018, the NIS sampling frame was changed to include only a cell phone sample (referred to as single cell-frame sampling). While the inclusion of cell phones resulted in the need to revise the baselines and targets of many HP2020 objectives, the change from dual frame to single cell-frame sampling of respondents had a minimal effect on national estimates of all 6 breastfeeding indicators examined (ever breastfed, breastfed at 6 and 12 months, exclusive breastfeeding through 3 and 6 months, and formula supplementation before 2 days among breastfed infants); national prevalence estimates differed by 0.2 percentage points or less.

      The following webpage outlines all of the changes that were made to the NIS in 2011 and 2018.
      https://www.cdc.gov/breastfeeding/data/nis_data/methods.html.

Revision History

Any change to the objective text, baseline, target, target-setting method or data source since the Healthy People 2020 launch.

Description of Changes Since the Healthy People 2020 Launch: 
In 2012, the word 'breastfeed' was changed to 'breastfed' to reflect the data collected in the survey. Specifically, the NIS data relate to infants who are breastfed, not mothers who breastfeed. The baseline for this objective was revised in 2019 due to a change in the methodology used to track this measure. The baseline year was revised from 2006 to 2009. The baseline was revised from 22.7% to 24.6%. In keeping with the original target setting method (projection/trend analysis), the target remained 34.1%.

References

Additional resources about the objective

  1. CDC. NIS survey methods.
  2. Smith PJ, Zhao Z, Wolter KM, Singleton JA, Nuorti JP. Age-period-cohort analyses of public health data collected from independent serial cross-sectional complex probability sample surveys. Seattle, WA: Joint Statistical Meeting; 2006.