Statistical Methods
Fourfold tables were analyzed by x2 analysis and by Fishers exact test when appropriate. The duration of hospitalization was compared by the Mann-Whitney U-test because of the inability to verify normal theory assumptions for these distributions. Foisson regression modeling was carried out using the GLIM statistical package. Terms were kept in a model if hierarchically necessary or if their removal resulted in an increase in the scaled deviance such that the resulting p value was less than 0.05. Global comparisons of discharge rates and mortality were made by incidence density methods.
Results
In order to examine seasonal differences, the data for hospital discharges were cross-tabulated into 64 cells (seasonal table) based on age, race, sex, calendar quarter, and location. The latter three were categorized in the obvious way, while the former two were categorized in an attempt to achieve balance and avoid sparse cells. Because the US Army is largely composed of whites and blacks, the racial categories are black and nonblack (ie, all other). The two age groups employed were ages less than or equal to 24 yr and ages greater than 24 yr. To examine differences in secular trend, a similar contingency table (secular table), with 80 cells, was constructed with a calendar year axis replacing that for quarter in the preceding table. It was not possible to model a single table incorporating both secular and seasonal effects simultaneously due to the extremely unbalanced nature of race, age, and sex groups in present army demography. The resulting contingency tables of discharge frequencies are depicted in Tables 1 and 2, with population denominators in parentheses. A Poisson regression model was fit to these tables, and the resulting estimates of discharge rates per 100,000 person-yr are seen in Tables 3 and 4. In order to facilitate the comparison of rates in the two locations for the seasonal table, Figures 1 and 2 depict the incidence density ratios (Europe/CONUS) for corresponding cells for each sex group. zyrtec tablets

Table 1—Observed Discharge Frequencies by Calendar Quarter for the Entire Period, 1984-88

Europe CONUS
>24 yr ^24 yr >24 yr <24 yr
Quarter Sex Nonblack Black Nonblack Black Nonblack Black Nonblack Black
1 F 14 (6,181) 13 (5,844) 7 (8,574) 8 (5,813) 34 (15,489) 11 (10,889) 31 (21,878) 11 (13,110)
M 91 (60,573) 23 (32,810) 22 (89,310) 14 (31,310) 134 (140,336) 67 (57,221) 114 (205,485) 45 (64,518)
2 F 15 (6,239) 13 (5,912) 7 (8,740) 12 (5,950) 32 (15,522) 19 (11,064) 22 (20,743) 6 (12,587)
M 86 (60,446) 64 (32,384) 49 (89,298) 25 (31,080) 136 (140,549) 88 (57,497) 126 (198,332) 68 (62,299)
3 F 25 (6,391) 41 (6,179) 20 (8,677) 14 (5,966) 21 (15,568) 19 (11,235) 20 (21,339) 15 (12,499)
M 94 (61,342) 173 (33,028) 115 (88,850) 100 (30,606) 99 (140,354) 73 (57,347) 148 (205,837) 82 (63,741)
4 F 18 (6,471) 15 (6,276) 12 (8,657) 11 (5,598) 37 (15,729) 22 (11,501) 32 (21,197) 16 (12,827)
M 64 (61,491) 48 (32,795) 40 (89,392) 24 (30,683) 117 (140,784) 64 (57,754) 141 (201,901) 88 (62,337)

Table 2—Observed Discharge Frequencies by Calendar Year

Year Sex Europe CONUS
>24 yr <24 yr >24 yr ^24 yr
Nonblack Black Nonblack Black Nonblack Black Nonblack Black
1984 F 10 (4,523) 8 (3,775) 13 (6,463) 14 (4,529) 30 (11,126) 8 (7,242) 17 (17,841) 14 (10,778)
M 76 (49,111) 49 (27,021) 48 (71,683) 39 (27,474) 110 (102,460) 47 (41,884) 134 (162,058) 62 (54,913)
1985 F 24 (4,805) 19 (4,526) 12 (6,802) 8 (4,820) 26 (11,262) 12 (7,572) 25 (17,007) 17 (9,856)
M 75 (48,428) 71 (26,814) 44 (70,809) 33 (24,855) 121 (103,491) 58 (42,454) 115 (162,342) 57 (51,179)
1986 F 8 (5,126) 15 (5,211) 8 (7,327) 12 (4,981) 24 (11,846) 14 (8,170) 26 (16,144) 4 (9,264)
M 59 (48,007) 50 (25,980) 45 (72,320) 30 (23,683) 84 (104,810) 49 (42,884) 101 (159,168) 50 (48,072)
1987 F 11 (5,404) 23 (5,404) 8 (7,244) 8 (4,7596) 21 (12,185) 15 (9,078) 23 (15,619) 8 (9,471)
M 62 (48,431) 69 (25,466) 49 (73,136) 31 (23,715) 91 (105,007) 65 (43,788) 95 (151,649) 60 (45,898)
1988 F 19 (5,423) 17 (5,296) 5 (6,811) 3 (4,597) 23 (12,306) 22 (9,859) 14 (14,463) 5 (9,400)
M 63 (49,875) 69 (25,744) 40 (68,901) 30 (23,951) 80 (103,284) 73 (43,260) 84 (140,534) 54 (43,288)

Table 3—Expected Discharge Rates per 100,000 Person-yr by Calendar Quarter Resulting from Seasonal Regression Model

Quarter Sex Europe CONUS
>24 yr <24 yr >24 yr <24 yr
Nonblack Black Nonblack Black Nonblack Black Nonblack Black
1 F 257.80 208.04 59.08 151.76 209.28 105.36 148.92 80.28
M 147.04 72.72 26.80 42.08 96.60 116.24 54.72 70.48
2 F 241.72 294.08 79.16 127.96 200.68 139.04 110.16 76.40
M 142.16 184.08 54.96 94.56 97.36 159.32 63.12 103.36
3 F 399.84 641.76 224.08 257.24 137.00 173.24 92.20 116.32
M 152.32 527.88 130.04 322.32 70.32 126.48 72.04 129.36
4 F 307.56 279.24 116.64 142.24 229.44 160.68 155.28 152.16
M 101.00 138.68 46.88 86.44 83.76 116.92 69.40 135.52

Table 4—Expected Discharge Rates per 100,000 Person-yr by Calendar Year Resulting from Secular Regression Model

Year Sex Europe CONUS
>24 yr <24 yr >24 yr <24 yr
Nonblack Black Nonblack Black Nonblack Black Nonblack Black
1984 F 321.09 227.55 151.24 176.31 225.17 125.75 157.06 144.29
M 154.12 187.96 72.59 145.62 108.07 103.88 75.38 119.19
1985 F 347.56 318.47 140.64 169.05 243.71 175.99 146.05 138.35
M 166.82 263.05 67.50 139.66 116.97 145.39 70.10 114.30
1986 F 243.88 252.14 130.31 148.54 171.02 139.35 135.32 121.56
M 117.07 208.28 62.54 122.70 82.09 115.11 64.95 100.43
1987 F 255.04 334.35 130.45 169.49 178.85 184.80 135.46 138.72
M 122.41 276.21 62.61 140.00 85.84 152.65 65.02 114.59
1988 F 254.29 349.66 114.45 149.96 178.31 193.26 118.85 122.75
M 122.05 288.86 54.93 123.89 85.58 159.64 57.04 101.40

Figure-1
Figure 1. Expected incidence density ratios of hospital discharges by calendar quarter. Height of bar reflects rate in Europe relative to CONUS for male subjects.

 Figure-2

Figure 2. Expected incidence density ratios of hospital discharges by calendar quarter. Height of bar reflects rate in Europe relative to CONUS for female subjects.

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