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  3. HIV prevention in Mexican schools: prospective randomised evaluation of intervention
Research

HIV prevention in Mexican schools: prospective randomised evaluation of intervention

BMJ 2006; 332 doi: https://doi.org/10.1136/bmj.38796.457407.80 (Published 18 May 2006) Cite this as: BMJ 2006;332:1189

Data supplement

  • Annex: Actually treated analysis

    Table A

    Table  B

    Table  C


    Table A Descriptive statistics by sex and intervention group at 16 month follow-up* (actually treated)

    [Posted as supplied by the authors]

     

    Comparison group

    Condom Promotion intervention

    Condom promotion *EC intervention

     

    Women

    Men

    Women

    Men

    Women

    Men

    Sex

    		 

    46%
    (43% - 49%)

    		 

    43%
    (34% - 51%)

    		 

    44%
    (40% - 48%)

    N

    		 

    998

    		 

    987

    		 

    1320

    Age

    16.72
    (16.65 - 16.80)

    16.79
    (16.64 - 16.95)

    16.85
    (16.76 - 16.93)

    16.89
    (16.77 - 17.02)

    16.73
    (16.66 - 16.80)

    16.91
    (16.79 - 17.03)

    N

    1151

    973

    1263

    942

    1640

    1257

    Significant other

    45%
    (39% - 50%)

    37%
    (34% - 40%)

    53%
    (50% - 56%)

    39%
    (35% - 44%)

    46%
    (44% - 49%)

    38%
    (35% - 41%)

    N

    1153

    959

    1277

    952

    1648

    1281

    Age of significant other

    18.77
    (18.38 - 19.17)

    17.08
    (16.82 - 17.33)

    19.12
    (18.66 - 19.57)

    16.95
    (16.71 - 17.20)

    18.98
    (18.72 - 19.24)

    16.89
    (16.77 - 17.01)

    N

    506

    354

    668

    370

    752

    481

    HIV Knowledge

    40.54
    (39.83 - 41.25)

    40.15
    (39.50 - 40.79)

    40.90
    (40.56 - 41.24)

    40.67
    (40.27 - 41.08)

    41.58
    (41.16 - 41.99)

    41.22
    (40.69 - 41.74)

    N

    1160

    971

    1302

    964

    1649

    1299

    EC Knowledge

    63%
    (57% - 69%)

    61%
    (56% - 66%)

    60%
    (55% - 66%)

    60%
    (54% - 65%)

    83%
    (78% - 87%)

    77%
    (72% - 83%)

    N

    1099

    898

    1238

    899

    1584

    1213

    Would use condom

    74%
    (68% - 81%)

    57%
    (52% - 63%)

    75%
    (72% - 79%)

    57%
    (53% - 60%)

    81%
    (77% - 84%)

    58%
    (53% - 63%)

    N

    628

    660

    756

    644

    980

    895

    Would stop sex to wear a condom

    93%
    (91% - 94%)

    81%
    (77% - 84%)

    93%
    (92% - 95%)

    83%
    (80% - 86%)

    94%
    (92% - 96%)

    82%
    (78% - %86)

    N

    853

    787

    978

    785

    1343

    1052

    Would condition sex on condom use

    98%
    (97% - 99%)

    91%
    (89% - 93%)

    98%
    (96% - 99%)

    92%
    (90% - 93%)

    98%
    (97% - 99%)

    93%
    (91% - 95%)

    N

    1012

    779

    1111

    755

    1469

    1051

    Sexually active

    18%
    (15% - 21%)

    27%
    (24% - 31%)

    18%
    (15% - 21%)

    27%
    (22% - 32%)

    16%
    (13% - 19%)

    29%
    (26% - 33%)

    N

    1137

    939

    1268

    919

    1626

    1247

    *Adjusted for cluster design using an estimation that identify schools as primary sampling units. Numbers in bold indicate a 95% significant difference between intervention group(s) with the comparison group; number in italics indicate a 95% significant difference between men and women within the group (intervention A, B or comparison).

     

      

    Table B Descriptive statistics by sex and intervention group for sexually active students* (actually treated)

    [Posted as supplied by authors]

     

    Comparison group

    Condom Promotion intervention

    Condom Promotion + EC intervention

     

    Women

    Men

    Women

    Men

    Women

    Men

    Condom use at first intercourse

    41%
    (30% - 52%)

    39%
    (35% - 43%)

    47%
    (43% - 50%)

    40%
    (34% - 46%)

    56%
    (50% - 62%)

    40%
    (33% - 46%)

    N

    201

    255

    224

    246

    256

    357

    Condom use at last intercourse

    42%
    (33% - 50%)

    49%
    (42% - 55%)

    46%
    (41% - 52%)

    51%
    (44% - 57%)

    48%
    (42% - 54%)

    50%
    (44% - 56%)

    N

    200

    245

    219

    245

    255

    349

    Sexual intercourse with sex worker, casual partner or compensated sex

    3%
    (2% - 5%)

    30%
    (24% - 37%)

    11%
    (3% - 18%)

    36%
    (33% - 40%)

    6%
    (4% - 9%)

    33%
    (28% - 38%)

    N

    126

    206

    141

    196

    164

    287

    Condom use with sex worker, casual partner or compensated sex

    75%
    (31% - 119%)

    69%
    (61% - 78%)

    67%
    (50% - 84%)

    80%
    (68% - 93%)

    50%
    (21% - 79%)

    85%
    (81% - 90%)

    N

    4

    62

    15

    71

    10

    95

    Used emergency contraception

    22%
    (16% - 29%)

    15%
    (10% - 20%)

    22%
    (17% - 27%)

    21%
    (16% - 25%)

    35%
    (28% - 42%)

    21%
    (16% - 25%)

    N

    201

    238

    219

    233

    256

    341

    Positive to HSV 2 antibodies

    23%
    (5% - 42%)

    17%
    (0% - 34%)

    32%
    (24% - 39%)

    29%
    (19% - 40%)

    17%
    (4% - 29%)

    12%
    (0% - 23%)

    N

    158

    170

    208

    215

    223

    276

    Had an older sexual partner

    23%
    (16% - 29%)

    22%
    (18% - 27%)

    33%
    (26% - 39%)

    29%
    (23% - 35%)

    31%
    (28% - 35%)

    23%
    (19% - 27%)

    N

    191

    234

    205

    222

    245

    324

    Had experience condom slippage

    32%
    (24% - 39%)

    32%
    (27% - 37%)

    21%
    (12% - 31%)

    31%
    (25% - 37%)

    23%
    (17% - 28%)

    33%
    (29% - 36%)

    N

    149

    186

    160

    179

    204

    280

    Had experience condom breakage

    22%
    (12% - 31%)

    16%
    (11% - 20%)

    15%
    (9% - 20%)

    19%
    (14% - 24%)

    14%
    (9% - 20%)

    16%
    (11% - 21%)

    N

    148

    185

    161

    184

    204

    284

    *Adjusted for cluster design using an estimation that identify schools as primary sampling units. Numbers in bold indicate a 95% significant difference between intervention group(s) with the comparison group; number in italics indicate a 95% significant difference between men and women within the group (intervention A, B or comparison).

     

      

    Table C Multivariate logistic regression to estimate impact of intervention on selected outcome variables (actually treated analysis, fixed effect models to correct for cluster design) [Posted as supplied by authors]

     

    HIV Knowledge*

    EC Knowledge

    Would use condom

    Would stop sex to wear a condom

    Condom use at first intercourse

    Condom use at last intercourse

    Had used EC

    Intervention CP = 1

    1.25

    (0.96 – 1.55)

    1.13
    (0.96 - 1.34)

    1.17
    (0.92 - 1.48)

    1.40
    (1.07 - 1.84)

    1.22
    (0.83 - 1.78)

    1.17
    (0.80 - 1.70)

    1.01
    (0.62 - 1.65)

    Intervention CP+EC = 1

    1.15

    (0.86 – 1.43)

    2.90
    (2.44 - 3.44)

    1.00
    (0.80 - 1.26)

    1.16
    (0.90 - 1.50)

    1.12
    (0.78 - 1.61)

    1.05
    (0.73 - 1.51)

    1.91
    (1.19 - 3.08)

    Follow-up = 1

    1.54

    (1.32 – 1.75)

    2.45
    (2.17 - 2.76)

    1.66
    (1.40 - 1.97)

    1.33
    (1.10 - 1.61)

    1.02
    (0.77 - 1.34)

    0.71
    (0.54 - 0.93)

    1.07
    (0.74 - 1.54)

    Male = 1

    -0.10

    (-0.22 – 0.01)

    0.98
    (0.91 - 1.05)

    0.53
    (0.48 - 0.58)

    0.43
    (0.39 - 0.48)

    0.83
    (0.71 - 0.97)

    1.43
    (1.22 - 1.67)

    0.72
    (0.60 - 0.88)

    Age at baseline

    -0.06

    (-0.13 – 0.01)

    1.01
    (0.97 - 1.06)

    0.93
    (0.88 - 0.98)

    1.04
    (0.97 - 1.10)

    0.95
    (0.88 - 1.03)

    0.90
    (0.84 - 0.97)

    0.94
    (0.85 - 1.04)

    Ever sexually
    active = 1

    0.52

    (0.37 – 0.67)

    1.45
    (1.33 - 1.59)

    0.66
    (0.60 - 0.74)

    0.76
    (0.67 - 0.85)

    na+

    na+

    na+

    N

    16708

    16129

    8226

    12220

    3024

    2985

    2871

    Prob > Chi2

    0.0000

    0.0000

    0.0000

    0.0000

    0.0214

    0.0000

    0.0000

    Results in bold are significant at 95%. + not applicable because these models only include sexually active participants

    *This dependent variable (HIV knowledge index) is treated as a continuous variable 0-36 and is therefore the only regression that is not logistic (and therefore significance is measure as a value different from 0), and instead of Chi2, it refers to a F test.

     



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