Introduction to Population-Disease Metrics
Importance of Metrics in Public Health
Population-disease metrics play a vital role in directing resources toward health interventions and executing public health initiatives. However, such data is not always accessible for every disease.
Utilizing Google for Population-Disease Metrics
In situations where traditional sources are unavailable, Google may serve as a useful alternative for obtaining population-disease metrics. This study explores Google’s efficacy in predicting cancer mortality rates.
The Role of Google Trends in Health Information
Google as a Primary Information Source
The internet has become the foremost resource for information on a broad spectrum of topics, including health-related issues. Google, as a leading search engine, aggregates data from user searches and compiles it into reports known as Google Trends.
Understanding Google Trends Data
Google Trends data is normalized based on total search volume, meaning data points are adjusted according to the total searches within a specific geography and time frame. Results are displayed as Search Volume Indices (SVIs) on a scale of 0 to 100. For example, the state with the highest relative search volume for a particular topic receives an SVI of 100, while other states with lower search volumes receive lower scores. This data can be leveraged for various objectives, potentially helping to estimate disease impact when validated population-disease metrics are not available.
Research Findings by Wehner et al.
Study Overview
Wehner and colleagues studied the relationship between total internet search volumes for prevalent cancer types and published cancer mortality and incidence rates across the United States. Their work was published in the Journal of the American Medical Association Dermatology.
Methodology and Data Collection
The researchers gathered Google search volume data through Google Trends to assess relative search volumes for ten common cancer types in all 50 states and the District of Columbia from 2009 to 2013. The cancers analyzed included breast, bladder, colorectal, lung, non-Hodgkin lymphoma, melanoma, prostate, and thyroid, which are recognized by the Centers for Disease Control and Prevention’s National Program of Cancer Registries as the most common in the U.S. This search data was then compared with age-adjusted cancer incidence and mortality rates for the same period.
Key Findings
The analysis revealed a positive association between state-specific Google search volumes and cancer incidence and mortality rates for several types of cancer, including colon, lung, lymphoma, and melanoma. These results highlight the potential of using internet search data and publicly available information to estimate disease characteristics like incidence and mortality rates.
Limitations of the Study
Generalizability Concerns
Wehner and colleagues identified several limitations in their study. Firstly, the use of Google search data may not be generalizable to the entire population, as it is limited to Google users.
Challenges with Rare Diseases
Secondly, the findings may not apply to rare diseases or conditions lacking a commonly searched term, which may not yield significant search volume data on Google Trends.
Variability of Search Volume
Lastly, search volume may fluctuate independently of actual disease metrics, particularly during public health campaigns aimed at raising awareness or screening for specific diseases, which could render the comparison of incidence and mortality rates between diseases inappropriate.
Conclusion
Despite its limitations, the study indicates that Google Trends can provide some predictive insights into cancer mortality rates. This information could be beneficial for informing policy and funding decisions when more reliable sources are unavailable.
References
Written by Sara Alvarado BSc, MPH
Wehner, M., Nead, K., Linos, E. (2017). Correlation among cancer incidence and mortality rates and internet searches in the United States. DOI: 10.1001/jamadermatol.2017.1870