08:00
EPID 684
Spatial Epidemiology
University of Michigan School of Public Health
Jon Zelner
[email protected]
epibayes.io
How do segregation measures map onto the mechanisms that drive health?
Coming to grips with the measurement of segregation and its impact on the spatial and social distribution of health outcomes
Segregation and COPD risk
Segregation and STI risk
The many measures of segregation employed by Biello et al.
Often defined as the proportion of contacts an individual in a minority group in a population has with members of that same group.
Interaction quantifies the proportion of minority group member’s contacts that occur with the majority group.
\[ Z = \sum_{i} \frac{a_{i}}{A} \frac{a_{i}}{n_i} \]
Where:
\[ D = \frac{1}{2} \sum_{i=1} \mid \frac{a_i}{A} - \frac{b_i}{B} \mid \]
Where:
Some canonical definitions from (1):
“They may be spatially centralized, congregating around the urban core, and occupying a more central location than the majority.”
“[A]reas of minority settlement may be tightly clustered to form one large contiguous enclave, or be scattered widely around the urban area.”
The spatial expression of social inequality is complex.
Our measures are necessarily reductive, and that’s OK…
IF and only IF (⟺) we use these measures carefully without losing sight of the mechanisms and outcomes we care about.
In pairs: In this google doc, brainstorm 🧠 ⛈️ some ideas about what dimensions of inequity these different measures capture.
08:00
Take 2m on your own to take a look back at the readings.
What struck you as interesting/confusing/frustrating?
What gaps do you see in the relationship between the segregation measures and disease outcomes assessed?
“Isolation may increase the risk for gonorrhea through its effect on social factors as well. Social norms — which also can be transmitted — have been shown to be associated with sexual risk among adolescents and among Black women. In isolated communities, within group norms for risky sexual behavior might be strengthened.” (2)
Segregation is a construct reflecting a complex mix of social and environmental factors.
Total effect: Relationship between distal factor and outcome including direct and indirect effects.
Direct effect: Relationship between distal factor and outcome adjusted for mediator.
Indirect effect: Impact of distal factor via a more proximal one.
In an additive model: indirect = total - direct