Table 2 Linear regression models for preterm birth rates, according to Regional Health Office. Paraná, Brazil, 2000-2013

1^st Paranaguá

y = 6.92 + 0.10x

0.11

0.283

Constant

2^nd Metropolitana

y = 7.00 + 0.22x

0.70

0.001

Growing

3^rd Ponta Grossa

y = 5.19 + 0.16x + 0.05x²

0.69

0.002

Growing

4^th Irati

y = 4.95 + 0.40x + 0.07x²

0.97

<0.001

Growing

5^th Guarapuava

y = 4.60 + 0.19x + 0.09x²

0.83

<0.001

Growing

6^th União da Vitória

y = 6.77 + 0.30x

0.74

<0.001

Growing

7^th Pato Branco

y = 6.48-0.95x + 0.27x²

0.86

<0.001

Declining

21^st Telêmaco Borba

y = 5.87 + 0.18x

0.18

0.163

Constant

West

8^th Francisco Beltrão

y = 6.21 + 0.26x

0.73

<0.001

Growing

9^th Foz do Iguaçu

y = 6.19 + 0.23x

0.57

0.004

Growing

10^th Cascavel

y = 6.93 + 0.12x + 0.06x²

0.71

0.001

Growing

20^th Toledo

y = 7.59 + 0.20x

0.21

0.130

Constant

Northeast

11^th Campo Mourão

y = 5.87-0.29x + 0.07x² + 0.02x³

0.89

<0.001

Declining/Growing

12^th Umuarama

y = 8.02 + 0.09x

0.56

0.005

Growing

13^th Cianorte

y = 5.97 + 0.30x

0.75

<0.001

Growing

14^th Paranavaí

y = 5.53 + 0.34x + 0.07x²

0.93

<0.001

Growing

15^th Maringá

y = 7.90 + 0.47x

0.91

<0.001

Growing

North

16^th Apucarana

y = 7.00 + 0.85x

0.89

<0.001

Growing

17^th Londrina

y = 8.59 + 0.34x

0.92

<0.001

Growing

18^th Cornélio Procópio

y = 6.22 + 0.18x + 0.07x²

0.76

0.001

Growing

19^th Jacarezinho

y = 5.26 + 0.30x

0.60

0.003

Growing

22^nd Ivaiporã

y = 7.96 + 0.11x

0.24

0.110

Constant