Extrarelational sex among Mexican men and their partners' risk of HIV and other sexually transmitted diseases.

OBJECTIVES: This study explored the risk of HIV and other sexually transmitted diseases (STDs) among married and cohabiting women in Mexico City, Mexico, derived from their partners' sexual behaviors. METHODS: Results were derived from the first population-based household survey in Mexico that investigated male sexual behavior. Analyses were restricted to sexually active married or cohabiting men (n = 3990). RESULTS: Fifteen percent of the men reported extrarelational sex during the past year, 9% reported condom use during last intercourse, and 80% perceived no HIV risk. Most secondary partners were coworkers, mistresses, or friends. CONCLUSIONS: Targeted HIV and STD prevention efforts appear necessary because a substantial number of women may be at risk.

[Validity and reproducibility of a questionnaire on physical activity and non-activity for school children in Mexico City]. / Validez y reproducibilidad de un cuestionario de actividad e inactividad física para escolares de la ciudad de México.

OBJECTIVE: To assess the validity and reproducibility of a self-reported questionnaire on physical activity and inactivity, developed for children aged 10-14 in Mexico City. MATERIAL AND METHODS: Between May and December 1996, a self-reported physical activity and inactivity questionnaire was developed and applied twice to a sample of 114 students aged 10 to 14, from a low and middle income population of Mexico City. The children's mothers completed the same questionnaire, and two 24-hour recalls of physical activity were used for comparison. Statistical analysis consisted of central tendency and dispersion measures and Pearson's correlation coefficient. RESULTS: Correlations between hours per day spent in physical activity and inactivity from the children's questionnaire and the 24-hour recall data, were 0.03 for moderate activity, 0.15 for vigorous activity, and 0.51 (p = 0.001) for watching television, adjusted by age, gender, town, and illness prior to the administration of the questionnaire. Compared to the 24-hour recall data, the questionnaire overestimated the time spent watching television, reading or participating in vigorous activity, and underestimated the time engaged in moderate activity. Statistically significant (p < 0.05) six-month reproducibility values were observed for watching television (r = 0.53), sleeping (r = 0.40), moderate (r = 0.38), and vigorous activity (r = 0.55). CONCLUSIONS: Among children of Mexico City aged 10-14, the questionnaire showed acceptable validity in estimating the time watching television, and acceptable reproducibility of the time watching television, vigorous and moderate activity.

Assessment of non-response bias in a probability household survey of male same-gender sexual behavior.

OBJECTIVE: To assess non-participation bias in a survey of male sexual behavior. MATERIAL AND METHODS: A household survey was carried out in 1992-1993 using a probability sampling frame in Mexico City. Demographic variables were available for all eligible men. The extent of non-participation bias was estimated using a version of the Heckman method, which utilizes two equations, one to predict participation and the other to predict reports of same-gender sexual behavior. RESULTS: A total of 8,068 of the 13,713 eligible men completed a face-to-face questionnaire (response rate 59%); 173 men (2.1%) reported bisexual behavior in their lifetime, and 37 (0.4%) reported only male partners. Survey participation was predicted using demographic variables: 67% of the observations were correctly predicted by a probit regression model: 82% of participants and 53% of non-participants (pseudo-r2 = 0.13). Same-gender sexual behavior was predicted by variables indicating attachment to gay/bisexual social networks, history of sexually transmitted diseases, positive attitudes towards gay and bisexual males, and lack of support from male relatives. Ninety-seven per cent of the cases was correctly predicted by the probit model (pseudo-r2 = 0.14). The correlation between these two equations was not statistically significant. CONCLUSIONS: These results indicate that prevalence estimates of same-gender sexual behavior among Mexico City men were not biased by selective survey participation. Careful selection and training of household interviewers may have assisted in minimizing potential bias.

Association of obesity with physical activity, television programs and other forms of video viewing among children in Mexico city.

OBJECTIVE: To assess the association of physical activity, television program viewing and other forms of video viewing with the prevalence of obesity among school children. DESIGN: Cross-sectional study. SUBJECTS: 712 children, 9-16 y old, from a low- and a middle-income town in the Mexico City area. MEASUREMENTS: Children completed a self administered questionnaire to assess time spent in physical activity and television viewing, and diet. Height weight and triceps skinfolds were measured. The outcome variable was obesity, and the covariates were hours of television programs and other video viewing, physical activity, energy intake, percentage of energy from fat, town of location of school, age, gender and perception of mother's weight status. RESULTS: Among 461 children with complete information, 24% were classified as obese. Children reported an average of 4.1 +/- 2.2 h/d watching television (2.4 +/- 1.5 h/d for TV programs and 1.7 +/- 1.5 h/d for video cassette recorder (VCR) or videogames), and 1.8 +/- 1.3 h/d in moderate and vigorous physical activities. Odds ratios (OR) of obesity were 12% higher for each hour of television program viewing per day (OR = 1.12, 95% confidence interval (CI) 1.02,-1.22), and 10% lower for each hour of moderate/vigorous physical activity per day (OR = 0.90, 95% CI 0.83-0.98), controlling for age, gender, town and perception of mother's weight status. Children in the middle-income town had higher adjusted odds of obesity (OR = 2.58, 95% CI 1.47-4.54). CONCLUSION: Physical activity and television viewing, but not VCR/videogames use, were related to obesity prevalence in Mexican children 9-16 y old.

Stress and incidence of bleeding in children and adolescents with hemophilia.

OBJECTIVE: To examine the relationship of stress and incidence of bleeding in boys with hemophilia. STUDY DESIGN: We conducted a 6-month longitudinal study of 97 subjects (ages 4 to 16 years) from six hemophilia centers. Diaries recorded bleeding episodes (including site and history of previous trauma) and both child and parent daily stress. Parent and child stressful life event measures were obtained monthly. Socioeconomic data and clotting factor level were determined at enrollment. Logistic regression models examined the influence of recent stress on likelihood of bleeding on each day, controlling for factor level and socioeconomic data. We also determined associations of aggregated previous month's events with bleeding likelihood in the succeeding month. RESULTS: Fifty-eight percent of study participants had severe hemophilia. The sample population averaged nine bleeding episodes per 6 months; of these; two thirds of bleeding incidents occurred into joints and 44% after injury. Factor level strongly predicted bleeding incidence (p < 0.0001). Increased parent stress was associated with increased bleeding in general (odds ratio = 1.37, p < 0.003) and with injury (odds ratio = 1.65, p < 0.001), but not bleeding into joints. Similar findings followed parent reports of positive life events. Increased parent negative life events in 1 month were associated with increased bleeding in the succeeding month (p < 0.05). CONCLUSION: Short- and long-term parental stress may lead to increased bleeding incidence in hemophilia, although factor level much more strongly predicts bleeding.

[The homosexual transmission of HIV/AIDS in Mexico]. / Transmisión homosexual del VIH/SIDA en México.

OBJECTIVE: To analyze HIV homosexual transmission in Mexico, epidemic trends and biological and social risk factors. METHODS: This analysis is based on 19,090 notifications of AIDS cases and on a review of two previous studies that include 3,029 behavioral interviews (together with HIV serological screening tests) carried out at the Information Center of the Mexican Council for Control and Prevention of AIDS (CONASIDA) (1988-89) and during a 1988 study in six Mexican cities. Cities were included because they were the larger in the country and/or because they were the larger in the country and/or because they were touristic places (Mexico City, Guadalajara, Monterrey, Acapulco, Tijuana and Merida). Logistic regressions were used to estimate the odds ratios for HIV seropositivity and for condom use. RESULTS: Seventy-two percent of the total reported AIDS cases (19,090) up to June 30, 1994, were associated with male homosexual behaviors. In absolute numbers, cases under this category exhibited a rising trend until the end of 1993. HIV seroprevalence was 31% in 2,314 men with homosexual practices who attended "FLORA", the AIDS Information Center in Mexico, from January 1988 to June 30, 1989. The main predictive variables for seropositivity were exclusive homosexual behavior, more than 40 lifetime sexual partners, mixed sexual behavior (both insertive and receptive and intercourse), sex with a person with AIDS, history of syphilis, and anal or genital warts. In general, these risk factors (data from the Information Center) are similar to those found in the six Mexican cities study. There were significant differences in HIV prevalence among the high-risk city samples (the highest in Mexico City with 25% and the lowest in Monterrey with 2.4%). Reported condom use was very low in both studies: only 5% used a condom in all of their sexual relationships. A statistically significant protective effect for HIV infection was found only for those who reported using a condom in all sexual encounters. In the six cities study, city of residence was a strong predictor of condom use. CONCLUSIONS: HIV homosexual transmission is steadily increasing; the recent decline in the percentage of homosexual cases is artificial because of the increment of cases under other categories. Men who report exclusive homosexual behavior have higher prevalence rates of infection than bisexual men. Individuals with insertive/receptive behavior (mixed) have the highest risk for HIV seropositivity, mainly because of sociological, rather than biological reasons. This difference in risks for HIV and condom use may be related to the selection of sexual partners from specific social networks. Condom use was demonstrated to be an effective method for preventing HIV seropositivity among those who always use condoms. However, it is alarming that only 5% of respondents reported condom use in all sexual encounters. Social and geographic differences in the cumulative numbers of cases, HIV prevalence, sexual practices and condom use must be taken into account in the planning of preventive programs.

HIV-1 seropositivity and behavioral and sociological risks among homosexual and bisexual men in six Mexican cities.

We report on the epidemiology of sexual behaviors, HIV-1 seroprevalence, and condom use in gay and bisexual men in six Mexican cities in 1988 and test the extent to which variations in sexual behavior and sociological risks are responsible for variations in prevalence. Seroprevalence rates among samples in six cities ranged from 2% to 25%. In multiple logistic regression models controlling for city, insertive/receptive behavior (IRB), and meeting partners in bathhouses, the following were independently related to seropositivity (p less than 0.05): city, IRB, syphilis, sex with a person with AIDS, and meeting partners in bathouses. The independent risks associated with categories of IRB were no or almost no activity (odds ratio 1.0), only insertive (3.0), mostly insertive (4.9), mixed (6.0), mostly receptive (3.3), and only receptive (0.9). The condom use rate on last sexual encounter was 30%. The main sexual risk for HIV-1 infection is not exclusively receptive anal sex, but rather mixed behavior. This association may be explained by the infectious state of the partner pools. The sociologic risk variables (national and local partner pools) are better predictors of seroprevalence than behavioral variables, such as the number of partners or use of condoms. These results imply that more effective individual strategies for risk reduction are needed, including better knowledge concerning the risk status of partners.

Very low birth weight children: behavior problems and school difficulty in a national sample.

We addressed three questions concerning the behavioral and academic status of low and very low birth weight infants through a secondary analysis of the 1981 National Health Interview Survey--Child Health Supplement: (1) in children born with very low birth weight, what is the risk of behavior problems and school difficulty compared with that in heavier low birth weight and normal birth weight children? (2) What are the correlates of school difficulty? (3) Are behavior problems associated with school difficulty when variables are controlled for these correlates? The analysis revealed that 34% of very low birth weight children could be characterized as having school difficulty, compared with 20% and 14% of the other groups, respectively, and that they were more likely to have higher scores on the hyperactive subscale of the Behavior Problems Index. Although a broad array of sociodemographic factors correlated with school difficulty, very low birth weight and hyperactivity scores contributed independently to the risk of academic problems. We conclude that very low birth weight infants are at risk of having school problems that are in part associated with hyperactive behavior.