# Presentation: 915318

## Age Adjustment Issues in Healthy People 2010

- John Aberle-Grasse, MPH
- National Center for Health Statistics

## Calculation of age-adjusted rate

- Age-adjusted rate =
- i (mi*wsi)
- 	mi  = di / pi * 100,000
- 	wsi = standard population weight in age group i
- 	di   = deaths in age group i
- 	pi  = population in age group i

## Calculation of age-adjusted rate

- Spreadsheet vs. “manual” calculation

- NCHS continues to use “manual” method

- Healthy People 2010 rate calculations are rounded/truncated to one decimal place

- Weights are rounded/truncated to six places

## Slide 4

## Standard population-  a population based on some age distribution

- NCHS in the past

- mortality data used 1940 standard

- survey data used mostly 1970 & 1980 standard

- NCHS now uses year 2000 US resident population as standard for all age adjustment

## Slide 6

## Standard population-  a population based on some age distribution

- NCHS in the past

- mortality data used 1940 standard

- survey data used mostly 1970 & 1980 standard

- NCHS now uses year 2000 US resident population as standard for all age adjustment

- 2000-adjusted rates better reflect national demographics and current crude rates

## Crude and age adjusted death rates based on year 1940 and 2000 standard populations: United States, 1979-2000

- Crude and age adjusted death rates based on year 1940 and 2000 standard populations: United States, 1979-2000

**1940 standard**

**2000 standard**

**crude rate**

## Slide 9

## Standard population-  a population based on some age distribution

**IMPORTANT REMINDER:** Comparisons can only be made between rates calculated using the _same_ standard population

## Slide 11

## Slide 12

## Age-adjustment inHealthy People 2010

- Health outcomes, risk factors, and health services data

- Age-adjustment inHealthy People 2010

## Diabetes prevalence by race/ethnicity (Obj. 5-3), 1999

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

**Overall**

**American Indian/ **
**Alaska Native**

**Asian/ **
**Pacific Islander**

**Hispanic/ **
**Latino**

**Not-Hispanic**
**White**

**Not-Hispanic **
**African American**

## Diabetes age specific rates, 1999

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

## 2000 Census age distribution

## Diabetes prevalence (Obj. 5-3), 1999

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

## Diabetes prevalence (Obj. 5-3), 1999

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

## Age-adjustment inHealthy People 2010

- Main purposes:
- Observe trends in populations over time
- Monitor disparity between populations both at a point in time and over time

- Health outcomes, risk factors, and health services data

- Age-adjustment inHealthy People 2010

## Standard population-  age distributions

- Several different age groupings are used to age-adjust data from different sources

## Data systems 					Age distributions used

## Slide 22

## Standard population-  age distributions

- Several different age groupings are used to age-adjust data from different sources

- Some data sources use fewer age groupings to stabilize the rates of less common events and smaller subpopulations (e.g. age groups for chronic disease)

## Hispanics aged 2+ years with diabetes who have seen a dentist in the past year (Obj. 5-15)

- Crude

- Age-adjusted

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

## Hispanics aged 2+ years with diabetes who have seen a dentist in the past year (Obj. 5-15)

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

## Hispanics aged 2+ years with diabetes who have seen a dentist in the past year (Obj. 5-15)

- Crude

- < 45 separate

- < 45 combined

- Source: National Health Interview Survey (NHIS), CDC, NCHS.

## Slide 27

## Some exceptions

- Data that are not age-adjusted

- National Household Survey on Drug Abuse

- Occupational injury and death

- Fatality Analysis Reporting System

- Census of Fatal Occupational Injuries

- Maternal/Infant mortality
- 	(live births as denominator)

## Some exceptions

- When to be careful in age-adjusting

- Age specific rates for a measure vary  differently between two population groups

## Slide 30

## Age specific cancer death rates among females, 1970 to 1995

- 1995

- 1970

- Source: National Vital Statistics System, CDC, NCHS.

## Slide 32

## Female cancer death rates, by age adjustment standard

- 1940 standard
- population

- 2000 standard
- population

- Source: National Vital Statistics System, CDC, NCHS.

- Crude rate