Table 1.
Key sample characteristics, 1987-2011
| Overalla | New casino | Pre-existing, expanding casino | Never casino | |
|---|---|---|---|---|
| Zip codes (n) | 124 | 65 | 11 | 47 |
| Newborns (n) | 21011 | 13878 | 2694 | 4438 |
| Slot machines per capita,b mean (SD) | 2.8 (4.7) | 3.3 (5.3) | 5.1 (3.5) | 0.0 (0.0) |
| 1-year lagged slot machines per capitab in 1987, mean (SD) | 0.2 (1.1) | 0.0 (0.0) | 3.0 (2.5) | 0.0 (0.0) |
| Slot machines per capitab in 2011, mean (SD) | 5.7 (6.9) | 7.3 (7.5) | 6.5 (4.2) | 0.0 (0.0) |
| Overall mean prevalence of LGA births among Native Americans (1987-2011),c,dn (%) | 2403 (11%) | 1635 (12%) | 340 (13%) | 428 (10%) |
| Prevalence of LGA among Native American newbornsd in 1987, n (%) | 77 (13%) | 52 (13%) | 8 (17%) | 17 (13%) |
| Prevalence of LGA among Native American newbornsd in 2011, n (%) | 125 (10%) | 78 (10%) | 19 (10%) | 28 (11%) |
| Overall mean BMI among Native American mothersd,e (2007-11), mean (SD) | 28.3 (7.1) | 28.2 (7.1) | 28.6 (7.2) | 28.3 (7.1) |
| Overall mean prevalence of excessive GWG among Native American mothersd,f (2007-11), n (%) | 3505 (56%) | 1984 (58%) | 461 (52%) | 625 (59%) |
| Overall mean prevalence of SGA births among Native Americansd,g (1987-2011), n (%) | 1885 (9.0%) | 1203 (8.7%) | 253 (9.4%) | 429 (9.7%) |
| Prevalence of SGA births among Native Americansd in 1987, n (%) | 49 (8.4%) | 35 (8.7%) | 4 (8.3%) | 10 (7.5%) |
| Prevalence of SGA births among Native Americansd in 2011, n (%) | 109 (8.9%) | 63 (8.0%) | 22 (11%) | 23 (9.6%) |
| Maternal age (years) | 25 (6) | 25 (6) | 25 (6) | 25 (6) |
| Maternal smoking during pregnancy, n (%) | 1983 (11%) | 1335 (12%) | 140 (6%) | 508 (14%) |
| Maternal education, n (%) | ||||
| < High school | 4730 (28%) | 3018 (27%) | 701 (30%) | 1010 (29%) |
| High school complete | 7523 (44%) | 4941 (44%) | 1016 (44%) | 1566 (44%) |
| Some college | 3764 (22%) | 2477 (22%) | 489 (21%) | 798 (23%) |
| College degree and higher | 960 (6%) | 681 (6%) | 119 (5%) | 160 (5%) |
| Parity (including current birth), mean (SD) | 2.4 (1.5) | 2.3 (1.5) | 2.4 (1.5) | 2.4 (1.5) |
There is one zip code that had a casino that was pre-existing and did not expand. Only one birth to a Native American occurred in this zip code during the observation period. This birth is included in the models, but key characteristics for pre-existing, non-expanding casinos are not provided since only one birth occurred in that category.
Slots per capita refers to the total number of casino slot machines in a zip code divided by the total number of American Indians living on tribal lands in that zip code, using the average population between 1990 and 2010 from the U.S. Census so that the denominator does not change. The distribution of slots per capita was right-skewed; median (IRQ) values were as follows. Slots per capita across all years: overall, 0.58 (0, 4.5); new, 1.4 (0, 4.5); pre-existing, expanding, 4.7 (3.0, 4.8); never, 0 (0,0). Slots per capita in 1987: overall (n = 581), 0 (0, 0); new (n = 401), 0 (0, 0); pre-existing, expanding (n = 48), 3.0 (1.1, 3.0); never (n = 132), 0 (0,0). Slots per capita in 2011: overall (n = 1220), 4.5 (0.0, 5.9); new (n = 781), 4.7 (2.0, 9.8); pre-existing, expanding (n = 190), 4.8 (4.5, 4.8); never (n = 249), 0 (0,0).
LGA births are defined as > 90th percentile compared with the Oken sex-and-gestational-age-specific reference population values.22
Race was self-reported on the birth certificate. For years allowing multiple race identifications (2000-11), we included newborns from women or men who answered American Indian to any of the race options.
Maternal pre-pregnancy BMI was based on self-reported pre-pregnancy weight and height and calculated as weight (kg)/height (m2). Sample size for 2007 and 2011 BMI are as follows. 2007: overall, 996; new, 646; pre-existing, expanding, 151; never, 199. 2011: overall, 1140; new, 730; pre-existing, expanding, 186; never, 224.
Gains were classified as excessive if a woman: was underweight (BMI < 18.5 kg/m2) and gained more than 18 kg; was normal weight (BMI ≥ 18.5 and < 25 kg/m2) and gained more than 15.9 kg; was overweight (BMI ≥ 25 and < 30 kg/m2) and gained more than 11.4 kg; or was obese (BMI ≥ 30 kg/m2) and gained more than 9 kg.
SGA births are defined as < 10th percentile compared with the Oken sex-and-gestational-age-specific reference population values.22