Table 4.
Urbanicity, Population Density and Data Zone-Level Heterogeneity by Individual- and Neighborhood-Level Adjustment Scenarios
| Basic adjustmenta,b | Full individual-level adjustmenta,c | |||
|---|---|---|---|---|
| Specific contextual effect | General contextual effect | Specific contextual effect | General contextual effect | |
| Measure of urbanizationd | Incidence Rate Ratio of neighborhood per 1 sd increase | Median Incidence Rate ratio (95% Probability Interval) | Incidence Rate Ratio of neighborhood per 1 sd increase | Median Incidence Rate Ratio (95% Probability Interval) |
| No adjustment for neighborhood-level covariates | ||||
| Population Density | 1.24 (1.20–1.29) | 1.30 (1.24–1.36) | 1.20 (1.16–1.25) | 1.24 (1.17–1.31) |
| Urbanicity | 1.98 (1.77–2.22) | 1.29 (1.22–1.35) | 1.78 (1.59–1.98) | 1.23 (1.16–1.30) |
| Adjusted for neighborhood-level covariatese | ||||
| Population Density | 1.08 (1.02–1.14) | 1.23 (1.15–1.29) | 1.08 (1.02–1.15) | 1.22 (1.14–1.28) |
| Urbanicity | 1.29 (1.10–1.50) | 1.22 (1.15–1.29) | 1.30 (1.11–1.51) | 1.21 (1.13–1.28) |
| Adjusted for neighborhood-level covariatese and other urbanization proxy | ||||
| Population Density | 1.06 (0.99–1.12) | 1.22 (1.15–1.29) | 1.06 (1.00–1.12) | 1.21 (1.13–1.28) |
| Urbanicity | 1.24 (1.06–1.45) | 1.22 (1.15–1.29) | 1.24 (1.06–1.46) | 1.21 (1.13–1.28) |
a Estimates were based on multilevel survival analyses, neighborhoods are 1885 novel data zones nested in Denmark’s 98 municipalities. The 579 039 people born in Denmark 1972–1981 were followed for development of schizophrenia. During the follow-up period from 1982 to 2016, a total of 5103 developed schizophrenia during the 17 191 889 person-years at risk
b Estimates were adjusted for individual-level age and its interaction with sex and neighborhood-level age distribution (Basic adjustment).
c Estimates were adjusted for Basic adjustment and individual-level residential instability, parental Charlson, parental death, parental imprisonment, parental age, parental history of mental disorders, parental income, parental employment status and parental education.
d Proxy measure for urbanization. For each data zone, population density was calculated as the number of inhabitants divided by the area, log transformed and thereafter standardized to unit standard deviation. The estimate for urbanicity measure the effect of residence in the most urban environment compared to residence in the most rural environment. It was included as a trend variable scored as Capital 1, capital suburb 0.75, provincial city 0.5, provincial towns 0.25, and rural area 0. Both variables were delineated at initiation of follow-up. Due to the different scales, effect sizes are not directly comparable in size.
e Neighborhood-level indicators were summarized using the first 3 Principal Components of all neighborhood-level covariates (excl. urbanicity and population density).