Table 4 Geographical clusters of LBWpre in Japan.
From: Detecting geographical clusters of low birth weight and/or preterm birth in Japan
Cluster | Cluster location | Number of municipalities | Expected cases | Observed cases | Relative risk | p value |
|---|---|---|---|---|---|---|
Total (n = 151,435) | ||||||
Most likely cluster | A3: Kagoshima (mainland), Okinawa and small islands between them | 78 | 5066.74 | 6726 | 1.33 | < 0.001 |
Second likely cluster | B3: Center of Tohoku area | 89 | 3939.28 | 4339 | 1.10 | < 0.001 |
Third likely cluster | C3: Kanmon-Kaikyo Straits between Honshu and Kyushu | 36 | 2266.57 | 2579 | 1.14 | < 0.001 |
Maternal age ≤ 20 (n = 3977) | ||||||
Most likely cluster | A3_1: Small islands in Kagoshima and Okinawa | 47 | 123.41 | 206 | 1.67 | < 0.001 |
Second likely cluster | B3_1: Center of Hiroshima | 14 | 53.88 | 78 | 1.45 | < 0.001 |
Third likely cluster | C3_1: Northwest of Tokyo | 3 | 13.05 | 28 | 2.15 | < 0.001 |
Maternal age (20, 35] (n = 105,792) | ||||||
Most likely cluster | A3_2: Kagoshima (mainland), Okinawa and small islands between them | 77 | 3539.77 | 4672 | 1.32 | < 0.001 |
Second likely cluster | B3_2: Center of Tohoku area | 81 | 2904.96 | 3155 | 1.09 | < 0.001 |
Third likely cluster | C3_2: Kanmon-Kaikyo Straits between Honshu and Kyushu | 38 | 1687.92 | 1883 | 1.12 | < 0.001 |
Maternal age > 35 (n = 41,655) | ||||||
Most likely cluster | A3_3: Kagoshima (mainland), Okinawa and small islands between them | 91 | 1251.77 | 1665 | 1.33 | < 0.001 |
Second likely cluster | B3_3: North part of Kanto Plain: Gunma, Tochigi and Fukushima | 81 | 1064.98 | 1260 | 1.18 | < 0.001 |
Third likely cluster | C3_3: Around Mt. Fuji | 42 | 653.15 | 804 | 1.23 | < 0.001 |
