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. Author manuscript; available in PMC: 2014 Sep 2.
Published in final edited form as: Arch Pediatr Adolesc Med. 2009 Mar;163(3):203–210. doi: 10.1001/archpediatrics.2008.563

Table 3.

Characteristics of Cases vs Matched Controls Aged 5 to 19 Years

No. (%)b
Characteristica Cases (n=27) Controls (n=79) P Valuec
Demographic
 Age, y, mean (SD) 14.0 (5.2) 13.7 (4.6) .06
 Sexd
  F      4 (15)      9 (11)
  M    23 (85)    70 (89)
 Race .09
  White    12 (48)    47 (68)
  Nonwhite    13 (52)    22 (32)
 Household income, $ .01
  >50000      5 (21)    39 (57)
  ≤50000    19 (79)    30 (43)
 Education of respondente .11
  >High school    10 (50)    45 (65)
  ≤High school    10 (50)    24 (35)
 Children <6yin household .88
  No    19 (83)    65 (82)
  Yes      4 (17)    14 (18)
Environmental
 Exposure to water, May–Sep, time/mo .11
   ≤1    10 (38)    18 (23)
   >1    16 (62)    61 (77)
 Exposure to water, Oct–Apr, time/mo .13
   ≤1    23 (88)    60 (76)
   >1      3 (12)    19 (24)
Health and development
 Risk taking score, ages 5–9 y, mean (SD) 2.15 (0.80) 1.87 (0.36) .32
 Sensation seeking score, ages 10–19 y, mean (SD) 2.30 (0.61) 2.44 (0.40) .44
 General health
  Excellent/very good/good    25 (100)    69 (100)
  Fair/poor      0      0
 Seizure disorder .005
  No    20 (80)    78 (100)
  Yes      5 (20)      0
 Other medical condition .38
  No    17 (65)    59 (76)
  Yes      9 (35)    19 (24)
Swimming lessons
 Formal .02
  No    19 (73)    37 (47)
  Yes      7 (27)    42 (53)
 Informal instructionf .45
  Never/rarely/sometimes      9 (41)    21 (30)
  Every or most of the time    13 (59)    49 (70)
Comfort in water
 Comfortable in water .81
  Uncomfortable/slightly uncomfortable      4 (17)    11 (14)
  Comfortable/very comfortable    20 (83)    67 (86)
 Comfortable putting whole head in water .32
   No      7 (28)    13 (19)
   Yes    18 (72)    56 (81)
 Comfortable in water to waist .02
  No      6 (24)      4 (6)
  Yes    19 (76)    66 (94)
 Comfortable jumping into water over his/her head .02
   No    11 (44)    15 (21)
   Yes    14 (56)    55 (79)
 Comfortable playing or swimming in water over his/her head .007
   No    12 (48)    15 (22)
   Yes    13 (52)    54 (78)
Swimming ability
 Float on back for 10 s .08
  No    11 (42)    20 (27)
  Yes    15 (58)    55 (73)
 Swim on stomach 15 ft .003
  No    14 (56)    15 (19)
  Yes    11 (44)    62 (81)
 Jump in a pool/swim 5 ft/back to wall .03
   No    10 (40)    15 (22)
   Yes    15 (60)    54 (78)
 Swim/take breath/continue .03
  No    10 (40)    16 (21)
  Yes    15 (60)    61 (79)
 Swim 50 ft .09
  No    12 (52)    23 (31)
  Yes    11 (48)    51 (69)
 Swim >1 min .01
  No    10 (42)    12 (16)
  Yes    14 (58)    64 (84)
a

Characteristic of case or control, except where specified in headings.

b

Totals vary slightly because of missing data; percentage of distribution based on a denominator of those with information.

c

P value from the Wald statistic of a conditional logistic regression model containing only that variable.

d

All cases and controls in the 5- to 19-year age group were matched by sex; therefore, the P value is not applicable.

e

Asked only if the respondent lived with the child.

f

Assessed by asking how often the child received informal instructions, pointers, or tips about swimming or water safety when he or she went swimming.