Cigarette smoking, sexually transmitted diseases, and HIV/AIDS

Self-perceived risk of STIs in a population-based study of Scandinavian women

OBJECTIVE

This study examined the associations between current behaviours/characteristics and self-perceived risk for STIs, among randomly selected women aged 18-45 years from Denmark, Norway and Sweden.

METHOD

A population-based, cross-sectional, questionnaire study (paper based, web based and telephone based) was conducted during 2011-2012. We compared medium-high STI risk perception with no/low risk perception. The associations were explored for women who had ever had sexual intercourse and for women with a new partner in the last 6 months using multivariable logistic regression.

RESULT

The overall prevalence of medium-high STI risk perception was 7.4%. It was highest among women aged 18-24 years (16.2%) and among the Danish women (8.8%). Number of new sexual partners in the last 6 months (≥3vs 0 partners, OR 14.94, 95% CI 13.20 to 16.94) was strongly associated with medium-high STI risk perception. Among women with a new partner in the last 6 months, lack of condom use increased medium-high STI risk perception (OR 1.73, 95% CI 1.52 to 1.96). Genital warts in the last year, binge drinking and being single were associated with increased risk perception and remained statistically significant after additional adjustments were made for number of new partners and condom use with new partners in the last 6 months.

CONCLUSION

Subjective perception of risk for STI was associated with women's current risk-taking behaviours, indicating women generally are able to assess their risks for STIs. However, a considerable proportion of women with multiple new partners in the last 6 months and no condom use still considered themselves at no/low risk for STI.

Determinants of Chlamydia, Gonorrhea, and Coinfection in Heterosexual Adolescents Attending the National Public Sexually Transmitted Infection Clinic in Singapore

BACKGROUND

Amidst recent trends in rising rates of chlamydia and gonorrhea among Singaporean adolescents, there are limited data on risk factors associated with these infections that may inform prevention strategies in this population.

METHODS

A cross-sectional study of chlamydia and gonorrhea positivity was conducted among 1458 sexually active heterosexual adolescents between 14 and 19 years old attending the national public sexually transmitted infection clinic from 2006 to 2013. The association with demographic and behavioral characteristics was assessed by crude prevalence ratio, and negative binomial regression modeling was used to obtain adjusted prevalence ratios (aPRs).

RESULTS

Chlamydia positivity was found in 23.6% of males and 36.6% of females, gonorrhea positivity in 33.1% of males and 15.9% of adolescent girl, and coinfection positivity in 10.2% of males and 10.1% of females. In multivariable analysis, chlamydia was positively associated with being Malay (aPR, 1.6; 95% confidence interval [CI], 1.1-2.1) and inconsistent condom use for vaginal sex (aPR, 6.5; 95% CI = 2.4-17.4) in males and with being Malay (aPR, 1.9; 95% CI = 1.5-2.4), inconsistent condom use for vaginal sex (aPR, 2.0; 95% CI = 1.1-3.9), and number of lifetime partners in females (aPR, 1.1; 95% CI = 1.0-1.1). Gonorrhea was positively associated with being Malay (aPR, 3.2; 95% CI = 2.4-4.4), inconsistent condom use for vaginal sex (aPR, 5.4; 95% CI = 2.1-14.4), and number of lifetime partners (aPR, 1.1; 95% CI = 1.0-1.1) in males and with being Malay (aPR, 3.7; 95% CI = 2.4-5.7) in females. Malays had a higher proportion of sexual risk behaviors compared with the non-Malays.

CONCLUSIONS

Ethnicity and high-risk sexual behaviors are important determinants of chlamydia, gonorrhea, and coinfection for adolescents attending this clinic. Targeted interventions are needed to lower the prevalence of high-risk sexual behaviors for the Malay adolescents in this clinic.

Assortative mixing as a source of bias in epidemiological studies of sexually transmitted infections: the case of smoking and human papillomavirus

For studies examining risk factors of sexually transmitted infections (STIs), confounding can stem from characteristics of partners of study subjects, and persist after adjustment for the subjects' individual-level characteristics. Two conditions that can result in confounding by the subjects' partners are: (C1) partner choice is assortative by the risk factor examined and, (C2) sexual activity is associated with the risk factor. The objective of this paper is to illustrate the potential impact of the assortativity bias in studies examining STI risk factors, using smoking and human papillomavirus (HPV) as an example. We developed an HPV transmission-dynamic mathematical model in which we nested a cross-sectional study assessing the smoking-HPV association. In our base case, we assumed (1) no effect of smoking on HPV, and (2) conditions C1-C2 hold for smoking (based on empirical data). The assortativity bias caused an overestimation of the odds ratio (OR) in the simulated study after perfect adjustment for the subjects' individual-level characteristics (adjusted OR 1·51 instead of 1·00). The bias was amplified by a lower basic reproductive number (R 0), greater mixing assortativity and stronger association of smoking with sexual activity. Adjustment for characteristics of partners is needed to mitigate assortativity bias.

Factors associated with syphilis infection: a comprehensive analysis based on a case-control study

This study aimed to comprehensively evaluate factors that influence the likelihood of syphilis infection from risk-taking behaviours and medical conditions. A retrospective case-control study was conducted by enrolling 664 syphilis inpatients (excluding 11 congenital syphilis patients) and 800 sex- and age-matched controls. Medical histories, clinical data and patient interview data were collected and subjected to logistic regression analyses. The prevalence of syphilis in the study population was 3·9% (675/17,304). By univariate analysis, syphilis infection was associated with migration between cities, marital status, smoking, reproductive history, hypertension, elevated blood urea nitrogen (BUN) and infection with hepatitis B virus (HBV) (P < 0·05). A high rate of syphilis-HBV co-infection was observed in HIV-negative patients and further research revealed an association between syphilis and specific HBV serological reactivity. Syphilis was also associated with the frequency, duration and status of tobacco use. Multivariate analysis indicated that syphilis infection was independently associated with migration between cities [adjusted odds ratio (aOR) 1·368, 95% confidence interval (CI) 1·048-1·785], current smoking (aOR 1·607, 95% CI 1·177-2·195), elevated BUN (aOR 1·782, 95% CI 1·188-2·673) and some serological patterns of HBV infection. To prevent the spread of infectious diseases, inpatients and blood donors should be tested for HIV, syphilis, HBV and HCV simultaneously.

Factors associated with unprotected sexual practice among men and women with mental illnesses in Brazil

This study estimated the rate and correlates of recent unprotected sex among sexually active psychiatric patients in Brazil, stratified by gender. The prevalence of unprotected sex among women and men were 89% and 77%, respectively. Significant correlates with unprotected sex were: being married/in union, living with children/partner, and cigarette smoking in both genders; lower income, depression and anxiety diagnoses among men only; older age, no previous HIV testing, sex under the influence of alcohol/drugs, and verbal violence among women only. Interventions to reduce risk behavior among psychiatric patients in Brazil are urgent and should take into account gender differences.

Human papillomavirus serology and tobacco smoking in a community control group

Background

HPV infection is an established risk factor for oropharyngeal cancer, and it has been proposed that cigarette smoking may potentiate HPV infection in the oral epithelium. We sought to test the hypothesis that cigarette smoking increases HPV infection in an HPV16 serology study of cancer-free individuals.

Methods

Subjects were participants in a risk factor study for head and neck cancer, and were required to have no prior history of either HNSCC or any other cancer. Tobacco use and other risk factor data were gathered through interviewer-assisted questionnaires, while serology was conducted in a blinded fashion using a glutathione S-transferase capture enzyme-linked immunosorbent assay (ELISA) to detect antibodies against HPV16 L1, E1, E2, E4, E6 and E7 proteins. The differences in tobacco use by HPV serology were evaluated by ANOVA; and the reported odds ratios and 95% confidence intervals were determined by using unconditional logistic regression.

Results

We found no overall association of HPV16 serological markers with smoking. However, when the data were stratified by median age, smoking was positively associated with seropositivity for the HPV16 L1 capsid antigen in the younger controls while the older controls were less likely to be HPV16 L1 positive if they smoked (p_interaction < 0.002). There was no similar association of smoking and age with serological response to the early proteins (i.e E6, E7).

Conclusions

Exposure to HPV16 capsid protein (L1) is increased among relatively younger adults who smoke and diminished among older smokers. However, this pattern is not accompanied by a differential susceptibility for active infection (as determined by the early gene proteins such as E6 and E7) among young and older smokers.

Prevalence and socioeconomic factors associated with smoking in people living with HIV by sex, in Recife, Brazil

INTRODUCTION

Smoking is the leading cause of preventable death in the world. The prevalence of smoking is higher in people infected with HIV than in the general population. Although it is biologically plausible that smoking increases the morbidity and mortality of people living with HIV/AIDS, few studies in developing countries have analyzed the determinants and consequences of smoking in HIV infected people.

OBJECTIVE

To estimate the prevalence of smoking and identify the socioeconomic factors associated with smoking and smoking cessation in patients with HIV by sex.

METHODS

A cross-sectional study was conducted with baseline data, obtained from an ongoing prospective cohort study of patients with HIV attending two referral centers in Recife, Northeast Region of Brazil, between July 2007 and October 2009.

RESULTS

The prevalence of current smoking was 28.9%. For both sexes, smoking was independently associated with heavy alcohol drinking and marijuana use. Among women, smoking was associated with living alone, not being married and illiteracy; and among men, being 40 years or older, low income and using crack. Compared with ex-smokers, current smokers were younger and more likely to be unmarried, heavy drinkers and marijuana users.

CONCLUSIONS

It is important to incorporate smoking cessation interventions for the treatment of heavy alcohol drinkers and marijuana users with HIV/AIDS, which may increase life expectancy and quality of life, as smoking is related to risk of death, relapse of tuberculosis, and non communicable diseases.

Neisseria gonorrhoeae and Chlamydia trachomatis infection in HIV-1-infected women taking antiretroviral therapy: a prospective cohort study from Burkina Faso

OBJECTIVES

Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) are common sexually transmitted infections (STI). We assessed the cumulative risk of NG and CT in a cohort of HIV-1-infected high-risk women taking antiretrovirals over 4 years in Burkina Faso.

METHODS

Between March 2007 and February 2011, participants were followed every 3-6 months. At each visit, participants underwent a gynaecological examination with collection of cervical and vaginal swabs. Random-effects logistic regression models were used to analyse associations of NG and CT infection with behavioural and biological factors.

RESULTS

172 women had samples tested for NG and CT during the study period, in a total of 1135 visits. NG was detected in 6.4% of women (11/172, 95% CI 2.7 to 10.1) at a rate of 2.76 cases (95% CI 1.53 to 4.99) per 100 person-years. CT was detected in 1.7% (3/172, 95% CI 0 to 3.7) of women at a rate of 0.75 cases (95% CI 0.24 to 2.34) per 100 person-years. The majority of women were asymptomatic (9/14). In the multivariable model, the presence of NG or CT was associated with tobacco use (aOR=11.85, 95% CI 1.13 to 124.17), and concurrent genital HIV-1 RNA shedding (aOR=4.78, 95% CI 1.17 to 19.46). Higher levels of education (aOR=0.17, 95% CI 0.03 to 0.92), and age greater than 35 years (aOR=0.07, 95% CI 0.01 to 0.92) were associated with lower odds of infection.

CONCLUSIONS

The risk of NG or CT infection remains low among high-risk women in Bobo-Dioulasso. This provides some evidence that antiretroviral use does not contribute to behavioural disinhibition. The asymptomatic nature of most infections underscores the need for regular screening and treatment of STIs in core groups.

Prevalence of weight-loss strategies and use of substances for weight-loss among adults: a population study

This paper concerns a cross-sectional population-based study conducted with adults living in the city of Pelotas, Rio Grande do Sul State, Brazil. It aims to determine the prevalence of weight-loss practices and use of substances for weight-loss during the 12 months preceding the interview. The prevalence of weight-loss attempts was 26.6%. Although dietary control and regular physical exercise were the most commonly used strategies, the prevalence of the combined use of these methods was only 36% for individuals trying to lose weight. The prevalence of use of substances for weight-loss was 12.8% (48.4% of those who tried to lose weight). The use of dietary control and substances was more common among women, while men practiced physical exercise with greater frequency. Teas were the most frequently used substances for weight-loss. Multivariate analysis identified being female, excess weight and self-perception of excess weight as major associated factors for the use of substances for weight-loss. Finally, we found that, although weight-loss attempts are common, the majority of obese individuals do not make attempts to lose weight and only a minority follows the recommended practices.

Sexually transmitted infections and risk of prostate cancer: review of historical and emerging hypotheses

Since the early 1950s when sexually transmitted infections (STIs) were first proposed as a possible risk factor for prostate cancer, numerous epidemiologic studies have been conducted. Initially, these studies were primarily small case-control studies with retrospective, self-reported assessments of a narrow range of STIs, typically either any STIs, or gonorrhea and syphilis. However, as new STIs have been discovered/recognized, new and better tests to detect histories of STIs have been developed, and new resources for prostate cancer research have been created, epidemiologic studies have expanded to include a wide range of STIs, and have moved towards more rigorous, prospective study designs and serological assessment of STI histories. The results of these studies are reviewed and discussed, as well as possible new avenues of research, such as Trichomonas vaginalis infection and infections not typically considered to be sexually transmitted.

Risk of Chlamydia trachomatis infection during pregnancy: effectiveness of guidelines-based screening in identifying cases

Our goal was to define the risk factors for Chlamydia trachomatis (CT) infection among pregnant women at a large urban medical centre. In a retrospective study, clinical records at a US maternity unit from July 2005 through February 2008 were reviewed. The study population included all pregnant women with a singleton newborn of at least 20 weeks gestation and antenatal care information. Logistic regression was used to analyse the association between a positive CT test and demographic, behavioural and prenatal care variables. A total of 2127 women were included in this analysis. The prevalence of CT infection was 4.7%. Cases were more likely to be younger, black and single. Other risk factors included tobacco use and Neisseria gonorrhoeae infection. Our findings suggest that factors other than age may impact upon the diagnosis of CT in pregnant women and that a more comprehensive testing strategy should be considered.

Correlates of sexually transmitted infection histories in a cohort of American male health professionals

OBJECTIVE

Several epidemiologic studies have investigated sexually transmitted infections (STIs) and later risk of genitourinary conditions with suggestive positive results. While these results may reflect causal associations, other possible explanations include confounding by factors possibly related to both STI acquisition and genitourinary condition risk such as recognized STI-risk factors/correlates, and other factors not typically considered in relation to STIs (e.g., general health-related behaviors or markers of such behaviors). Very few of these factors have been investigated in older populations in which STIs and genitourinary conditions are typically studied. Therefore, we investigated STI history correlates in one such population, the Health Professionals Follow-up Study.

METHODS

We ascertained histories of potential correlates, gonorrhea, syphilis by questionnaire (n = 36,032), and performed serologic testing for Chlamydia trachomatis, Trichomonas vaginalis, human papillomavirus, and human herpesvirus type 8 infection in a subset (n = 651).

RESULTS

Positive correlations were observed for African-American race, foreign birth, southern residence, smoking, alcohol consumption, ejaculation frequency, vasectomy, and high cholesterol. Inverse correlations were observed for social integration and routine health-related examinations.

CONCLUSIONS

These findings provide useful information on potential confounders for epidemiologic investigations of STIs and chronic diseases, and interesting new hypotheses for STI prevention (e.g., STI counseling before vasectomy).

Is smoking tobacco an independent risk factor for HIV infection and progression to AIDS? A systemic review

OBJECTIVES

To systematically review the evidence of the relation between smoking tobacco and HIV seroconversion and progression to AIDS.

METHODS

A systematic review was undertaken of studies to look at tobacco smoking as a risk factor for either HIV seroconversion or progression to AIDS.

RESULTS

Six studies were identified with HIV seroconversion as an outcome measure. Five of these indicated that smoking tobacco was an independent risk factor after adjusting for important confounders with adjusted odds ratios ranging from 1.6 to 3.5. 10 studies were identified using progression to AIDS as an end point of which nine found no relation with tobacco smoking.

CONCLUSIONS

Tobacco smoking may be an independent risk factor for HIV infection although residual confounding is another possible explanation. Smoking did not appear to be related to progression to AIDS although this finding may not be true in developing countries or with the longer life expectancies seen with highly active antiretroviral therapy.

Body mass index, sexual behaviour, and sexually transmitted infections: an analysis using the NHANES 1999-2000 data

Background

Factors determining human sexual behaviour are not completely understood, but are important in the context of sexually transmitted disease epidemiology and prevention. Being obese is commonly associated with a reduced physical attractiveness but the associations between body mass index, sexual behaviour and the risk of acquiring sexually transmitted infections has never been studied.

Methods

The National Health and Nutrition Examination Survey (NHANES) files of 1999–2000 were used. Linear regression was used to relate the reported number of sex partners in the last year and lifetime to Body Mass Index (BMI). Logistic regression was used to relate Herpes Simplex Virus type II (HSV-2) antibodies to BMI and other variables.

Results

Data on 979 men and 1250 women were available for analysis. Obese (mean number of partners for men:1.12, women: 0.93) and overweight (mean for men: 1.38, women: 1.03) individuals reported fewer partners than individuals of normal BMI (mean for men:2.00, women: 1.15) in the last year (p < .0.01 & p < 0.05 for men, p < 0.05 & n.s. for women). The same relationship held for lifetime partners in men (mean 11.94, 18.80, and 22.08 for obese, overweight and normal BMI respectively (p < 0.05 & n.s. for obese and overweight vs normal respectively), but not in women (mean 7.96, 4.77, and 5.24 respectively). HSV-2 antibodies were significantly correlated with the number of lifetime partners in both men and women, with the odds of being HSV-2 positive increasing by 0.6% (p < 0.01) and 2.7% (p < 0.01) for men and women respectively. HSV-2 antibodies increased with age, even after adjustment for lifetime partners (p < 0.01). Being obese (HSV-2 prevalence 15.9 and 34.9% for men and women respectively) or overweight (HSV-2 prevalence 16.7 and 29.3 for men and women respectively) was not associated with HSV-2 antibodies (HSV-2 prevalence for normal BMI: 15.6 and 23.2% respectively), independent of whether the association was adjusted for life time sexual partners or not. There was evidence of substantial misreporting of sexual behaviour.

Conclusion

Obese and overweight individuals, especially men, self report fewer sex partners than individuals of normal weight, but surprisingly this is not reflected in their risk of HSV-2 infection. HSV-2 antibodies provide information not contained in self-reported number of partners and may better estimate sexual risk than self-reported behaviour.

Spectrum of cancers among HIV-infected persons in Africa: The Uganda AIDS-Cancer Registry Match Study

Although more than 25 million people in sub-Saharan Africa have human immunodeficiency virus (HIV) infection, little is known regarding their cancer risk. We investigated cancer risk among persons with HIV/AIDS in Uganda using record-linkage. We linked records of 12,607 HIV-infected persons attending The AIDS Support Organization (TASO) in Kyadondo County from October 1988 through December 2002 to the Kampala Cancer Registry. We calculated standardized incidence ratios (SIRs) to identify increased cancer risks in the early (4-27 months after TASO registration), late (28-60 months), or combined (4-60 months) incidence periods. We identified 378 cancers (181 prevalent, 197 incident) among TASO participants. Of incident cancers, 137 (70%) were AIDS-defining cancers. Risk was increased in the early-incident period, compared to the general population, for the AIDS-defining cancers: Kaposi sarcoma (SIR 6.4, 95%CI 4.8-8.4), non-Hodgkin lymphoma (6.7, 1.8-17), and cervical carcinoma (2.4, 1.1-4.4). These three cancers were also increased in the combined periods. Risks of five non-AIDS-defining cancers were increased in the combined periods: Hodgkin lymphoma (5.7, 1.2-17) and cancers of the conjunctiva (SIR 4.0; 1.5-8.7), kidney (16, 1.8-58), thyroid (5.7, 1.1-16), and uterus (5.5, 1.5-14). Cancers of the breast, nasopharynx, and lung were increased either in the early or late incident periods only. Among 407 children, seven cancers were observed, of which five were Kaposi sarcoma. The application of a record-linkage design in Africa broadens the repertoire of epidemiological tools for studying HIV-infected populations. We confirm the increased risks of AIDS-defining cancers and report increased risks of a few non-AIDS-defining cancers.

Immune deficiency and risk for malignancy among persons with AIDS

BACKGROUND

People with AIDS have an elevated risk for cancer. We studied the relationship between cancer risk and AIDS-related immunosuppression as measured by CD4 count at AIDS onset.

METHODS

We linked records from AIDS and cancer registries in 11 US regions (1990-1996). We studied 82,217 (86.6%) adults who had a CD4 count measured at AIDS onset and survived into the follow-up period. We calculated standardized incidence ratios (SIRs) for AIDS-defining (Kaposi sarcoma [KS], non-Hodgkin lymphoma [NHL] and cervical cancer) as well as non-AIDS-defining cancers in the 2 years after AIDS onset. For each cancer, the change in SIRs across CD4 counts (0-49 cells/mm3, 50-99 cells/mm3, 100-199 cells/mm3, and > or =200 cells/mm3) was modeled using Poisson regression.

RESULTS

The SIRs for KS, NHL, and cervical cancer were 258, 78, and 8.8, respectively. For each fall of 100 CD4 cells/mm3, RRs were 1.36 (95% CI: 1.29-1.43) for KS and 1.48 (95% CI: 1.37-1.59) for NHL. Among NHL subtypes, the association with lower CD4 counts was strongest for immunoblastic lymphoma (RR =1.64, 95% CI: 1.37-1.96, per decline of 100 CD4 cells/mm3) and central nervous system lymphoma (RR = 2.29, 95% CI: 1.95-2.69). The SIR for cervical cancer did not vary with CD4 count (p =.74). For non-AIDS-defining cancers (overall SIR = 2.1), neither the combined risk nor the risk of specific types was associated with declining CD4 counts.

CONCLUSION

SKS and NHL risk increased with level of immunosuppression at AIDS onset. Risks for other cancers, including cervical cancer, were unrelated to CD4 counts. Elevated risks for non-AIDS cancers may be a result of lifestyle factors.

Factors associated with risk behaviors for sexually transmitted disease/AIDS among urban Brazilian women: a population-based study

BACKGROUND

The proportion of women among persons with sexually transmitted disease (STD)/AIDS in Brazil is increasing rapidly, and studies are needed to understand risk behaviors.

GOAL

The goal of this study was to identify factors associated with risk behaviors for acquiring STD/AIDS among women aged 15 to 49 years in Pelotas, Brazil.

STUDY DESIGN

A representative sample of women was surveyed by means of interviewer-administered and self-administered confidential questionnaires. Of the women we sought to include, 3.5% refused and 1543 participated.

RESULTS

Risk behaviors included nonuse of condoms (72%); first intercourse before the age of 18 years (47%); use of drugs or alcohol by the partner (14%) or by the woman (7%); multiple partners (7%); and anal sex (3%). The risk score was significantly associated with being younger than age 30 years, having <5 years of schooling, being divorced or separated, and being a smoker.

CONCLUSION

Preventive strategies should prioritize efforts toward young women, those with little schooling, smokers, and those who are divorced or separated.