MPH 510 Module 1 Descriptive Epidemiology Example

Who, Where and When: A Descriptive Epidemiology of US Drug Overdose Deaths, 2002-2022

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Master of Public Health Program, Aspen University

MPH 510: Epidemiology in Public Health

Instructor Name

Month Day, Year

Who, Where and When: A Descriptive Epidemiology of US Drug Overdose Deaths, 2002-2022

Epidemiology begins with description. Before investigators can test why a health problem occurs, they must know who is affected, where and when, and how often. Descriptive epidemiology answers those questions using counts and rates and, by revealing patterns, generates hypotheses about causes. This paper applies the person, place and time framework to drug overdose deaths in the United States over two decades.

Counts and Rates

In 2022, 107,941 people in the United States died of a drug overdose. A count alone cannot show whether risk is rising, because the population grows and ages. Rates divide deaths by the population at risk and multiply by a standard base, here 100,000 people. Age-adjusted rates go further, weighting each age group's rate to a standard population so that an older county and a younger one, or 2002 and 2022, can sit side by side without age skewing the picture.

Time

The age-adjusted overdose death rate nearly quadrupled, from 8.2 per 100,000 in 2002 to 32.6 in 2022, though the rate did not change significantly between 2021 and 2022 (Spencer et al., 2024). The trend is not a single smooth rise. Analysts describe three overlapping waves: deaths from prescription opioids rising from the late 1990s, heroin deaths rising from about 2010, and deaths involving illicitly made fentanyl rising sharply from about 2013 (Ciccarone, 2019). A fourth pattern, overdoses combining fentanyl with stimulants such as methamphetamine and cocaine, has grown in recent years.

Person

Rates differ by sex, age and race and ethnicity. The table summarizes selected figures from national vital statistics for 2022.

Shifting Age Patterns

Between 2021 and 2022, rates fell among adults aged 15 to 34 and rose among adults aged 35 and older, and adults 65 and older had the largest percent increase, 10.0% (Spencer et al., 2024). The shift suggests that an aging group of people who use drugs, many exposed during earlier waves, now faces the more lethal fentanyl supply.

Race and Ethnicity

From 2021 to 2022, age-adjusted rates rose for American Indian and Alaska Native, Black, Hispanic and Asian people, while the rate for White people did not rise (Spencer et al., 2024). In the early years of the epidemic, overdose deaths were concentrated among White Americans; the fentanyl era has spread the burden, with the steepest recent increases among Black and American Indian populations.

Place

Overdose rates vary widely by state and county, with some Appalachian, New England and Mountain West states far above the national average. Place patterns have shifted as the drug supply changed: fentanyl reached eastern markets earlier than western ones. Mapping county rates helps target resources such as naloxone distribution and treatment programs to the places with the greatest need.

Broader Context

Overdose deaths are part of a wider rise in what some economists call deaths of despair. An analysis of mortality in midlife found that death rates among White non-Hispanic Americans aged 45 to 54 rose between 1999 and 2013, reversing decades of decline, driven by drug and alcohol poisonings, suicide and chronic liver disease, with the largest increases among those with the least education (Case & Deaton, 2015). This context points toward economic and social causes alongside drug supply.

Generating Hypotheses

Descriptive patterns suggest questions for analytic studies. Why did rates rise among older adults while falling among younger ones? Do places with greater naloxone access or treatment capacity have lower death rates? Does the timing of fentanyl's arrival explain differences between regions? Each question could be tested with cohort, case-control or ecological designs.

Limitations of the Data

Death certificate data depend on how medical examiners and coroners investigate and record deaths, and practices vary. Some certificates do not specify the drugs involved, which undercounts specific substances. Race and ethnicity may be misclassified, particularly for American Indian and Alaska Native people. Recent data are provisional and may be revised.

Implications for Prevention

Descriptive findings shape priorities. The concentration among middle-aged and older adults argues for reaching people already using drugs, not only preventing initiation among the young. The dominance of synthetic opioids argues for naloxone, fentanyl test strips and rapid access to medications for opioid use disorder. Rising rates among Black and American Indian communities argue for culturally grounded services in those communities.

Crude Versus Adjusted

Crude and adjusted rates can tell different stories. A state with many older residents may have a low crude overdose rate simply because older adults overdose less often; after age adjustment, its rate may be close to the national figure. When comparing counties for funding decisions, analysts should use age-adjusted rates, and when planning services for a specific place, crude counts show how many people actually need help.

Using Descriptive Data Locally

A county health department can repeat this analysis with its own death certificate data, emergency department visits for nonfatal overdose and naloxone administrations reported by emergency medical services. Nonfatal overdoses are an early warning, since each one signals a person at high risk of a later fatal event. Weekly monitoring of these data allows rapid alerts when a potent new drug enters the local supply.

Communicating the Findings

Descriptive findings reach decision-makers best as simple charts: a line graph of rates over time, a bar chart by age group and a county map. Each should show rates rather than counts where comparisons are made, label the data source and year, and note when figures are provisional. Plain explanations of age adjustment help nontechnical readers trust the comparisons.

Timeliness

Final death data lag by about a year, so provisional counts are used for rapid response, with the understanding that they will be revised.

Conclusion

Describing overdose deaths by person, place and time reveals an epidemic that has changed shape across three waves, now concentrated among middle-aged and older adults and spreading across racial and ethnic groups under the influence of fentanyl. These patterns generate hypotheses for analytic study and point public health toward targeted, evidence-based responses.

References

Case, A., & Deaton, A. (2015). Rising morbidity and mortality in midlife among white non-Hispanic Americans in the 21st century. Proceedings of the National Academy of Sciences, 112(49), 15078-15083. https://doi.org/10.1073/pnas.1518393112

Ciccarone, D. (2019). The triple wave epidemic: Supply and demand drivers of the US opioid overdose crisis. International Journal of Drug Policy, 71, 183-188. https://doi.org/10.1016/j.drugpo.2019.01.010

Spencer, M. R., Garnett, M. F., & Miniño, A. M. (2024). Drug overdose deaths in the United States, 2002-2022 (NCHS Data Brief No. 491). National Center for Health Statistics. https://doi.org/10.15620/cdc:135849