Rachel C. Potter

A Pilot Study Associating Urinary Concentrations of Phthalate Metabolites and Semen Quality

Phthalates are ubiquitous industrial chemicals that are reported to adversely affect human reproductive outcomes. Divergent effects on semen quality have been reported in a limited number of studies. To assess the possible contribution of regional differences in phthalate exposure to these results, we wished to determine if ambient phthalate exposure of men from the Great Lakes region was associated with human sperm parameters. Male partners (N=45) of subfertile couples presenting to a Michigan infertility clinic were recruited. Urinary concentrations of several phthalate metabolites were measured in these men. Semen parameters, measured according to the World Health Organization [WHO 1999] protocols, were divided into those at or above WHO cutoffs for motility (50% motile), concentration (20thinsp;million/mL) and morphology (4% normal) and those below. Phthalate metabolite concentrations were divided into those concentrations above the median and those at or below the median. Specific gravity was used as a covariate in the regression models to adjust for urine dilution. Low sperm concentration was significantly associated with above median concentrations of monoethyl phthalate (MEP) (OR=6.5, 95% CI: 1.0–43.6) and low morphology with above median concentrations of mono-3-carboxypropyl phthalate (OR=7.6, 95% CI: 1.7–33.3). Increased odds for low concentration and above median concentrations of metabolites of di(2-ethylhexyl) phthalate (DEHP) (OR=5.4, 95% CI: 0.9–30.8) and low morphology and above median concentrations of MEP (OR=3.4, 95% CI: 0.9–13.8) were also found. A significant trend was observed for tertiles of MEP and low sperm concentration (p=0.05). Results suggest that ambient phthalate metabolite concentrations may adversely affect human semen quality.

Risk Factors for Sporadic Campylobacter jejuni Infections in Rural Michigan: A Prospective Case–Control Study

OBJECTIVES This case-control study investigated risk factors for campylobacteriosis in a rural population. Exposure to live farm animals was hypothesized to increase the risk for Campylobacter jejuni enteritis. METHODS Incident cases from rural counties reported to the Michigan Department of Community Health and matched controls completed a self-administered postal questionnaire. RESULTS Persons engaged in poultry husbandry had increased odds of campylobacteriosis (odds ratio = 6.884; 95% confidence interval (CI) = 1.438, 32.954). There was evidence for a dose-response relationship between the number of types of poultry contact and campylobacteriosis. CONCLUSIONS We estimate that 18% (95% CI = 6%, 30%) of Campylobacter cases occurring in rural populations are attributable to poultry husbandry. Cases occurred in individuals who were not poultry farmers by occupation.

Ambient manganese exposure is negatively associated with human sperm motility and concentration.

Background: Occupational and experimental animal studies indicate that exposure to high levels of manganese impairs male fertility, but the effects of ambient manganese in humans are not known. Methods: We measured blood levels of manganese and selenium in 200 infertility clinic clients in a cross-sectional study. Correlations between metals and semen variables were determined, adjusting for other risk factors. Outcomes were low motility (<50% motile), low concentration (<20 million/mL), or low morphology (<4% normal). We also investigated dose–response relationships between quartiles of manganese exposure and sperm parameters. Results: High manganese level was associated with increased risk of low sperm motility (odds ratio = 5.4; 95% confidence interval = 1.6–17.6) and low sperm concentration (2.4; 1.2–4.9). We saw a U-shaped dose–response pattern between quartiles of manganese exposure and all 3 sperm parameters. Conclusion: Ambient exposure to manganese levels is associated with a reduction in sperm motility and concentration. No adverse effects were seen for high selenium.

An application of multivariate ranks to assess effects from combining factors: Metal exposures and semen analysis outcomes

In studies of environmental effects on human health outcomes, it is often difficult to assess the effects of a group of exposure variables when the individual exposures do not appear to have statistically significant effects. To address this situation, we propose a method of U-scores applied to subsets of multivariate data. We illustrate the usefulness of this approach by applying it to data collected as part of a study on the effects of metal exposure on human semen parameters. In this analysis, profiles (pairs) of metals containing copper and/or manganese were negatively correlated with total motile sperm and profiles containing copper were negatively correlated with sperm morphology; profiles containing selenium and chromium were positively correlated with total motile sperm.

Assessing the Relationship Between Seasonal and H1N1 Influenza Vaccination Status in Michigan Children, 2009-2010

Objectives. To examine the relationship between the outcome of vaccination for H1N1 influenza and receipt of seasonal influenza vaccine in Michigan children during the 2009–2010 season, we examined the influenza vaccination status of all Michigan residents aged six months to 18 years who were enrolled in the Michigan Care Improvement Registry. Methods. We calculated descriptive statistics for dichotomous and categorical variables, including numbers of children vaccinated with either influenza A (H1N1) monovalent vaccine and/or seasonal influenza vaccine, gender, race/ethnicity, provider type, moved-or-gone-elsewhere (MOGE) status, and vaccine type. We used logistic regression, adjusting for potential confounders and effect modifiers (age and MOGE status), to calculate odds ratios associated with H1N1 vaccine status (vaccinated vs. unvaccinated). Results. Michigan children who were vaccinated for seasonal influenza from August 1, 2009, to February 27, 2010, were 6.26 (95% confidence interval 6.18, 6.34) times as likely as children who were unvaccinated for seasonal influenza to be vaccinated with H1N1 2009 monovalent vaccine. Private health-care providers administered 91% of the seasonal influenza vaccine and 59% of the H1N1 vaccine. Conclusions. Increasing seasonal influenza vaccination campaign efforts could also benefit pandemic influenza vaccination efforts. Special educational outreach to parents regarding the importance of influenza vaccination for all children, regardless of age, may be needed. Stocking and offering traditional seasonal vaccine with pandemic-specific vaccine may aid in increasing immunization uptake. Efforts should be made to ensure that private providers are supplied with adequate pandemic vaccine as part of preparedness planning.

Statewide Pandemic Influenza Vaccination Reminders for Children with Chronic Conditions

OBJECTIVES We evaluated the use of a statewide immunization information system (IIS) to target influenza vaccine reminders to high-risk children during a pandemic. METHODS We used Michigans IIS to identify high-risk children (i.e., those with ≥ 1 chronic condition) aged 6 months to 18 years with no record of pH1N1 vaccination among children currently or previously enrolled in Medicaid (n = 202,133). Reminders were mailed on December 7, 2009. We retrospectively assessed childrens eligibility for evaluation and compared influenza vaccination rates across 3 groups on the basis of their high-risk and reminder status. RESULTS Of the children sent reminders, 53,516 were ineligible. Of the remaining 148,617 children, vaccination rates were higher among the 142,383 high-risk children receiving reminders than among the 6234 high-risk children with undeliverable reminders and the 142,383 control group children without chronic conditions who were not sent reminders. CONCLUSIONS Midseason reminders to parents of unvaccinated high-risk children with current or past Medicaid enrollment were associated with increased pH1N1 and seasonal influenza vaccination rates. Future initiatives should consider strategies to expand targeting of high-risk groups and improve IIS reporting during pandemic events.

A Systematic Evaluation of Different Methods for Calculating Adolescent Vaccination Levels Using Immunization Information System Data

Objective. Immunization information systems (IISs) are valuable surveillance tools; however, population relocation may introduce bias when determining immunization coverage We explored alternative methods for estimating the vaccine-eligible population when calculating adolescent immunization levels using a statewide IIS. Methods. We performed a retrospective analysis of the Michigan State Care Improvement Registry (MCIR) for all adolescents aged 11–18 years registered in the MCIR as of October 2010. We explored four methods for determining denominators: (1) including all adolescents with MCIR records, (2) excluding adolescents with out-of-state residence, (3) further excluding those without MCIR activity ≥10 years prior to the evaluation date, and (4) using a denominator based on U.S. Census data. We estimated state- and county-specific coverage levels for four adolescent vaccines. Results. We found a 20% difference in estimated vaccination coverage between the most inclusive and restrictive denominator populations. Although there was some variability among the four methods in vaccination at the state level (2%–11%), greater variation occurred at the county level (up to 21%). This variation was substantial enough to potentially impact public health assessments of immunization programs. Generally, vaccines with higher coverage levels had greater absolute variation, as did counties with smaller populations. Conclusion. At the county level, using the four denominator calculation methods resulted in substantial differences in estimated adolescent immunization rates that were less apparent when aggregated at the state level. Further research is needed to ascertain the most appropriate method for estimating vaccine coverage levels using IIS data.

A Population-Level Assessment of Factors Associated With Uptake of Adolescent-Targeted Vaccines in Michigan

PURPOSE Increases in adolescent vaccine coverage are needed. The aim of this study was to identify population-level clinical and demographic factors associated with adolescent vaccination. METHODS A retrospective analysis of data from the Michigan Care Improvement Registry (MCIR), a statewide immunization registry, was performed for 2006-2010. The sample included 1,252,655 adolescents aged 11-18 years. Vaccine coverage levels were calculated for tetanus-diphtheria-acellular pertussis (Tdap), meningococcal conjugate (MCV4), flu (seasonal influenza), and human papillomavirus, females only (HPV) vaccines. For the subset of adolescents enrolled in Medicaid, claims data were used to obtain information about the type of visits in which vaccines were administered. RESULTS As of 2010, statewide coverage levels for Tdap and MCV4 vaccines were 46.0% and 46.5%, respectively whereas only 15% of females had completed the HPV vaccine series. Only one in four female adolescents were up to date for all three of these vaccines. Statewide coverage among adolescents for flu vaccine during the 2009-2010 season was 8%. Age was the most significant predictor of HPV vaccination, whereas health care-associated factors (provider type and childhood immunization history) were the strongest predictors for the other three vaccines. Older adolescents were less likely to have received the flu vaccine but more likely to have receive HPV vaccine doses than younger adolescents. Among Medicaid-enrolled adolescents, most Tdap, MCV, and first-dose HPV vaccines, but only 29% of flu doses, were administered during preventive visits. CONCLUSIONS Noted variability in adolescent vaccine coverage by age, vaccine type, and health care-associated factors provides a framework for developing future outreach activities to increase adolescent vaccine use.

Adolescent Immunization Coverage and Implementation of New School Requirements in Michigan, 2010

OBJECTIVES We examined the effect of Michigans new school rules and vaccine coadministration on time to completion of all the school-required vaccine series, the individual adolescent vaccines newly required for sixth grade in 2010, and initiation of the human papillomavirus (HPV) vaccine series, which was recommended but not required for girls. METHODS Data were derived from the Michigan Care Improvement Registry, a statewide Immunization Information System. We assessed the immunization status of Michigan children enrolled in sixth grade in 2009 or 2010. We used univariable and multivariable Cox regression models to identify significant associations between each factor and school completeness. RESULTS Enrollment in sixth grade in 2010 and coadministration of adolescent vaccines at the first adolescent visit were significantly associated with completion of the vaccines required for Michigans sixth graders. Children enrolled in sixth grade in 2010 had higher coverage with the newly required adolescent vaccines by age 13 years than did sixth graders in 2009, but there was little difference in the rate of HPV vaccine initiation among girls. CONCLUSIONS Education and outreach efforts, particularly regarding the importance and benefits of coadministration of all recommended vaccines in adolescents, should be directed toward health care providers, parents, and adolescents.

Prevention of influenza in mothers and infants

Evaluation of: Zaman K, Roy E, Arifeen SE et al. Effectiveness of maternal influenza immunization in mothers and infants. N. Engl. J. Med. 359(15), 1555–1564 (2008). Pregnant women and infants are at an increased risk for the complications of influenza. Severe disease, emergency department visits and hospitalizations occur as frequently in these groups as in the elderly and those with chronic diseases. None of the US FDA-licensed influenza vaccines are approved for use in infants under 6 months of age and, despite long-standing recommendations, pregnant women are rarely immunized against influenza. The paper under evaluation has an important place in scientific understanding and advancement. These data not only help to reassure providers and pregnant women that the current Advisory Committee on Immunization Practices recommendation for influenza vaccination in pregnancy is well founded, but also provide strong evidence for a neonatal benefit to maternal influenza vaccination.