WHO ARE THESE GUYS?

Venue-based sampling could bias estimates of HIV risk factors, according to an analysis of data from the National HIV Behavioral Surveillance System (NHBS).1 Between 2003 and 2005, the NHBS enrolled more than 11,000 men who have sex with men; 56% of them were enrolled at bars and clubs, and these men differed in some important ways from those enrolled at sex establishments (e.g., adult theaters and bookstores) or other types of venues. For example, those enrolled at sex venues were more likely than these men to be 30 or older (odds ratios, 1.8–3.8), black or Hispanic (1.6–1.7), and bisexual (1.7), and to have had 10 or more partners in the past year (4.8); they were less likely to visit gay venues frequently (0.5–0.6). Men enrolled at other types of venues were more likely than those enrolled at bars and clubs to be 30 or older (1.0–1.5) and less likely to use noninjection drugs (0.7). Given these and other differences by enrollment venue, the analysts conclude that “because there is no gold standard for sampling [the population of men who have sex with men], those conducting surveys must be aware of the potential biases of each sampling strategy.”

1. Voetsch AC et al., Comparison of demographic and behavioral characteristics of men who have sex with men by enrollment venue type in the National HIV Behavioral Surveillance System, Sexually Transmitted Diseases, 2012, 39(3):229–235.

ABORTION IS SAFER THAN CHILDBIRTH

The pregnancy-related mortality rate among U.S. women who have legal abortions is a fraction the rate among women who have a live birth, findings from an analysis using several national data sets show.1 For the period 1998–2005, maternal deaths occurred at a rate of 0.6 per 100,000 abortions and 8.8 per 100,000 live births. The risks of a variety of pregnancy-related complications—including urinary tract infection, mental health conditions, obstetric infection and postpartum hemorrhage—also were higher among women who gave birth than among those who had abortions. The analysts note that their data may underestimate the pregnancy-associated mortality risk because they excluded outcomes other than live births, and may overestimate the abortion-related risk because women having abortions “appear to be at higher underlying risk” than those who continue their pregnancies. Nevertheless, they consider “the public health evidence … clear and incontrovertible: induced abortion is safer than childbirth.”

1. Raymond EG and Grimes DA, The comparative safety of legal induced abortion and childbirth in the United States, Obstetrics & Gynecology, 2012, 119(2, part 1):215–219.

NOW SOME GOOD NEWS

The prevalence of chlamydia infection among 14–39-year-olds dropped by 40% between 1999–2000 and 2007–2008.1 Analyses of data from five rounds of the National Health and Nutrition Examination Survey reveal dramatic declines among men (53%), teenagers (48%) and whites (77%). Prevalence did not fall among women aged 14–25, the group targeted for routine annual screening, or among blacks. In 2007–2008, a total of 1.6% of respondents tested positive for chlamydia infection, but prevalence varied considerably by race: 0.3% among whites, 2.4% among Mexican Americans and 6.7% among blacks. “Existing activities addressing chlamydia prevention may be on the right track,” the analysts remark, “but there remains a need to reduce prevalence in populations at greatest risk as well as to reduce racial disparities.”

1. Datta SD et al., Chlamydia trachomatis trends in the United States among persons 14 to 39 years of age, 1999–2008, Sexually Transmitted Diseases, 2012, 39(2):92–96.

WHAT WENT WRONG?

In 19 states that participated in the Pregnancy Risk Assessment Monitoring System, half of teenagers who had an unintended pregnancy that led to a live birth in 2004–2008 had not been using contraceptives when they conceived.1 Asked to indicate all of the reasons that they or their partner had not used a method, 31% said that they had thought they could not get pregnant at the time, 24% that their partner had not wanted to use a method and 22% that they had not minded the possibility of pregnancy; smaller proportions reported that they had had difficulty obtaining a method, had experienced side effects or had believed themselves or their partner to be sterile (8–13% each). Hispanic teenagers were more likely than others to attribute their nonuse of contraceptives to thinking that they could not conceive at the time and were less likely than others to cite contraceptive side effects. Five states reported on the contraceptive methods teenagers had been using when they conceived; according to these data, 21% of young women had been relying on a highly effective method (sterilization, an IUD or a hormonal), 24% condoms and 5% a less effective method. Blacks were less likely than other young mothers to have been using highly effective methods.

1. Harrison AT, Gavin L and Hastings PA, Prepregnancy contraceptive use among teens with unintended pregnancies resulting in live births—Pregnancy Risk Assessment Monitoring System (PRAMS), 2004–2008, Morbidity and Mortality Weekly Report, 2012, 61(2):25–29.

FOR BETTER SEMEN, HOLD THE CHEESE

A study based on 99 men attending a fertility clinic in Massachusetts offers preliminary evidence that total dietary fat intake is negatively related to total sperm count and sperm concentration; the relationship appears to be driven by the consumption of saturated fats, which are found in cheese, meat and other animal products.1 On the other hand, levels of omega-3 polyunsaturated fats—the “good” fats found in fish, nuts and certain types of cooking oil—seem to be positively related to the proportion of sperm that are normally shaped, a characteristic that aids their ability to reach an egg. The researchers acknowledge that their study is only a first step in assessing the relationship between dietary fat intake and semen quality, and that it does not lend itself to causal interpretation.

1. Attaman JA et al., Dietary fat and semen quality among men attending a fertility clinic, Human Reproduction, 2012, doi:10.1093/humrep/des065, accessed Mar. 13, 2012.

EFFECTIVE BUT HARDLY USED

Inserted postcoitally, the copper IUD is the most effective method of emergency contraception available, and it has the added benefit of providing long-term protection against unintended pregnancy. So why is its use so scarce? In a 2006 survey of contraceptive providers in California, only 15% reported ever having recommended the copper IUD for emergency contraception.1 Analyses controlling for providers’ demographic and professional characteristics identified only two predictors of having recommended the copper IUD as an emergency contraceptive: feeling at least somewhat comfortable inserting the device (odds ratios, 2.2–2.4) and knowing that a broad range of women can appropriately be given IUDs (2.1). Characteristics that might have been expected to be related to recommending a postcoital IUD, but were not, included providers’ specialty, clinical training in IUD insertion and knowledge of the method’s attributes. The researchers believe that their findings show “important missed opportunities” for providers to offer a highly effective method to women at risk of unintended pregnancy.

1. Harper CC et al., Copper intrauterine device for emergency contraception: clinical practice among contraceptive providers, Obstetrics & Gynecology, 2012, 119(2, part 1):220–226.

DOES SEX EDUCATION HELP LOWER BIRTHRATES?

In a study based on nine years of data from 24 states in which the rate of births to 15–17-year-olds varied widely, preliminary analyses suggested that the broader the content of school sex education curricula, the lower the teenage birthrate.1 However, the relationship was no longer significant when state-level measures of poverty, race and ethnicity, violent crime, religiosity and political environment were taken into account. In the adjusted analyses, the adolescent birthrate was positively associated with state levels of poverty and religiosity, and with the presence of laws requiring parental consent for minors seeking abortions. The researchers point to the “paradox” of relatively high teenage birthrates’ occurring in the most conservative states and urge these states to “pragmatically identify methods” to reduce levels of adolescent childbearing.

1. Cavazos-Rehg PA et al., Associations between sexuality education in schools and adolescent birthrates: a state-level longitudinal model, Archives of Pediatrics & Adolescent Medicine, 2012, 166(2):134–140.

TEENAGERS AND HIV TESTING

HIV testing is not yet “a normal part of medical care” for sexually experienced teenagers: This is the conclusion that one group of analysts draws from an examination of data from the 2009 Youth Risk Behavior Survey.1 Among the nationally representative sample of high school students, fewer than one in four of those who had ever had intercourse had had an HIV test. An encouraging finding, however, was that the odds of having been tested were elevated among youth with certain behavioral risk factors for HIV: those who had ever used injection drugs or been forced to have sex, had not used a condom at last intercourse or reported more than three partners over their lifetime (odds ratios, 1.3–2.3). The odds also were higher among blacks than among whites (1.4) and were greater among 11th and 12th graders than among students in ninth grade (1.4 and 1.6, respectively). “Health care providers,” the analysts write, must “play a central role in encouraging sexually active adolescents to be tested.” Furthermore, because not all teenagers routinely see health care providers, “innovative approaches [to promoting HIV testing] outside the health care setting must also be pursued.”

1. Balaji AB et al., Association between HIV-related risk behaviors and HIV testing among high school students in the United States, 2009, Archives of Pediatrics & Adolescent Medicine, 2012, doi:10.1001/archpediatrics.2011.1131, accessed Jan. 3, 2012.

NEW STD RISK FACTOR

Consistent use of lubricants during receptive anal sex may be a risk factor for STDs.1 In a clinic-based study conducted in 2006–2009, men and women aged 18 and older were given an anal exam, had samples obtained from a rectal swab tested for STDs and completed computer-administered self-interviews. Among the 380 participants who reported having used a lubricant during receptive anal sex in the past month, the prevalence of infection was 5% overall; however, it was significantly higher among consistent lubricant users than among inconsistent users (10% vs. 3%). The data also yielded evidence suggestive of a link between STD risk and both the number and the type of lubricants used. In an analysis controlling for age, gender, study site and behaviors related to receptive anal intercourse, the only variable associated with STD infection was lubricant use: Consistent users had three times as high odds of infection as inconsistent users. While acknowledging the limitations of the study, the investigators note that anal intercourse “is an important factor” in STD transmission and that rectal microbicides are clearly needed.

1. Gorbach PM et al., The slippery slope: lubricant use and rectal sexually transmitted infections: a newly identified risk, Sexually Transmitted Diseases, 2012, 39(1):59–64.