The Cost-Per-Case Estimates
Using the cost-per-case estimates developed by Chesson et al. (2004) we calculated the direct medical cost of chlamydia, gonorrhea, syphilis, genital herpes, HPV, hepatitis B, and trichomoniasis for young persons aged 15 to 24 years in California. When gender-specific data were available and when costs differed considerably between genders, Chesson et al. (2004) calculated gender-specific cost-per-case estimates, resulting in gender-specific estimates for chlamydia, gonorrhea, genital herpes, and HPV. Furthermore, using gender-neutral cost-per-case estimates developed by Hutchinson et al. (2006), we also calculated the direct medical cost of HIV for young persons aged 15 to 24 years in California.
All estimated costs are the lifetime costs of new cases of STIs occurring among young persons aged 15 to 24 years during the year 2005 (i.e., incidence costs), rather than the total cost in 2005 of existing cases of STIs and their sequelae among individuals who were 15 to 24 years old at the time of infection (i.e., prevalence costs; Chesson et al., 2004). Both Chesson et al. (2004) and Hutchinson et al. (2006) used a 3% annual discount rate in their calculation of all lifetime costs. We adjusted all costs for inflation to year 2005 dollars using the medical care component of the consumer price index (Economic Report of the President, 2006).
To calculate the total direct medical cost for each STI, we multiplied the inflation-adjusted cost per case by the estimated total number of incident cases of each STI estimated to have occurred in 2005 among young persons aged 15 to 24 years. For the STIs for which a gender-specific cost per case was available, we multiplied the gender-specific cost per case by the gender-specific incidence estimate or we assumed a male-to-female ratio in a gender-neutral estimate.
Results Statewide
Young persons aged 15 to 24 years in California acquired 1.1 million new cases of eight major STIs in the year 2005. Estimates for individual STIs range from more than a half million new HPV cases and a quarter million new trichomoniasis cases, down to 380 new syphilis cases and 520 new hepatitis B cases. For contrast, the table also includes the number of newly reported cases in California in 2005, for those five STIs for which data are collected (C. Woodfil , California Department of Health Services, Immunization Branch, personal communication, January 13, 2007; California Department of Health Services, 2006a, 2006d). As can be observed, the estimated number of cases is higher than is the reported number of cases for all five reportable STIs.
Sexually Transmitted Infections. Part 3
Taking this decrease into consideration, we estimated 520,000 new HSV-2 infections among persons aged 15 to 24 years in the United States. (Gender-specific estimates were not available.) We then extrapolated the national estimate to California using a multiplier of 12.91%, which represents California’s proportional share of youth aged 15 to 24 years in the United States population. The multiplier was calculated using U.S. population estimates from the U.S. Census Bureau (2006) and California population estimates from the California Department of Finance (2007). This multiplier was chosen as a straightforward way to estimate how many of the national cases of genital herpes would occur in California based on the percentage of the U.S. population of young persons who live in California.
Human Papillomavirus (HPV)
HPV is not a reportable STI in California, and no reliable state or local incidence estimates exist. The national incidence estimate for HPV (4.6 million) calculated by Weinstock et al. (2004) was therefore extrapolated to California using the multiplier of 12.91%. In estimating the incidence of HPV among 15–24-year-olds, Weinstock et al. (2004) assumed that incidence among females reflects the incidence among males.
Hepatitis B
To estimate the true incidence of hepatitis B among young persons aged 15 to 24 years, we followed the calculation method of Weinstock et al. (2004). The Centers for Disease Control and Prevention has estimated that 8,000 new infections with the hepatitis B virus occurred in the United States in 2004 among 15–24-year-olds (A. Wasley, Centers for Disease Control and Prevention, Division of Viral Hepatitis, personal communication, August 1, 2006). We assumed that approximately half of these infections occurred among individuals who reported high-risk sexual activity (Weinstock et al., 2004). (Gender-specific estimates were not available.) We extrapolated the national estimates to California using the multiplier of 12.91%.
Trichomoniasis
For trichomoniasis, we extrapolated the national estimate (1.9 million) calculated by Weinstock et al. (2004) to California using the multiplier of 12.91%. Weinstock et al. (2004) assumed that 7.4 million new cases of trichomoniasis occurred in the United States in the year 2000. We assumed that the incidence remained the same in 2005. Furthermore, as did Weinstock et al. (2004), we assumed that 25% of new infections occurred in 15–24-year-olds. (Gender-specific estimates were not available.)
Human Immunodeficiency Virus (HIV)
The Office of AIDS at the California Department of Health Services has estimated there are between 6,788 and 8,988 incident cases of HIV in California each year (Facer, Ritieni, Marino, Grasso, & Social Light Consulting Group, 2001). Taking the midpoint of this range (7,888) and assuming that 75% of infections are acquired sexually and that 50% of sexually acquired HIV infections are contracted by individuals younger than 25 years (Weinstock et al., 2004), we estimated the number of new HIV infections among 15-24-year-olds in California. (Gender-specific estimates were not available.)
Sexually Transmitted Infections. Part 2
Chlamydia
To estimate the true incidence of chlamydia among young persons aged 15 to 24 years, we followed the method of Groseclose, Zaidi, DeLisle, Levine, and Louis (1996) and Weinstock et al. (2004). We first used data from the 2002 National Survey of Family Growth (NSFG; Centers for Disease Control and Prevention, 2006a) to estimate the percentage of sexually active U.S. women aged 15 to 24 years in ethnic or racial groups (i.e., Black, White, Hispanic, and other). We estimated the percentages separately for each year of age to account for age differences in sexual activity. We then applied these percentages to the California Department of Finance’s (2007) 2005 population estimates for females aged 15 to 24 years, thus obtaining the number of 15-24-year-old women who are sexually active and thus at risk for STIs.
We then used California-specific chlamydia prevalence-monitoring data for 2005 from the Region IX Infertility Prevention Project (California Department of Health Services, 2006e) to determine the percentage of women who screened positive for a chlamydial infection in family planning clinics. Using the number of sexually active women and the percentage of women who were positive for a chlamydial infection we calculated the number of prevalent infections for Black, White, Hispanic, and other women. Assuming that the duration of chlamydial infection in women is 0.96 years and that incidence of infection is its prevalence divided by duration (Chesson et al., 2004; Groseclose et al., 1999), we calculated the number of incident infections among women. To calculate the number of incident cases among men we assumed that the incidence among men equals that among women (Chesson et al., 2004; Groseclose et al., 1999).
Gonorrhea
To estimate the true incidence of gonorrhea among young persons aged 15 to 24 years in California we assumed that the cases reported to the California Department of Health Services (2006d) for this group in 2005 were underreported and under diagnosed by 50% (Weinstock et al., 2004). We estimated the number of incident cases separately for males and females.
Syphilis
We assumed that the cases of primary, secondary, and early latent syphilis reported to the California Department of Health Services (2005c) for young persons aged 15 to 24 years in 2005 were underreported and underdiagnosed by 20% (Weinstock et al., 2004). We estimated the number of incident cases separately for males and females.
Genital Herpes
Genital herpes is not a reportable STI in California, and no reliable state or local estimates of incidence exist. The herpes simplex virus type 2 (HSV-2) is the cause of most genital herpes. Weinstock et al. (2004) estimated that 640,000 new HSV-2 infections occurred among young persons in the United States in the 2000. This estimate was based on the assumption that the rate of genital herpes in 2000 had remained the same as the rate in 1985 (Weinstock et al., 2004). A recent study on the trends of herpes simplex virus type 1 and type 2 seroprevalence in the United States has shown, however, that the overall age-adjusted HSV-2 seroprevalence decreased by 19% between 1988–1994 and 1999–2004 (Xu et al., 2006).
Sexually Transmitted Infections
Sexually transmitted infections (STIs) can have considerable and long-lasting impact on the health and quality of life of individuals, in the form of infertility, ectopic pregnancies, dyspareunia, cancer, and increased susceptibility to HIV. Young persons aged 15 to 24 years acquire more than half of all new STIs every year (Weinstock, Berman, & Cates, 2004). National estimates show that 9.1 million new STIs occurred among 15-24-year-olds in the year 2000, the majority of which were due to human papillomavirus (HPV), trichomoniasis, and chlamydia (Weinstock, Berman, Cates, 2004).
Despite the progress over the last decade in screening and detecting STIs, especially among young persons, major obstacles remain to accurately monitoring the incidence and prevalence of STIs. Many STIs are asymptomatic and detected only through screening, not all STIs are reportable (e.g., HPV and trichomoniasis), and screening and reporting are not always complete for reportable STIs, which means that the true incidence of STI is likely to be substantially higher than the number of reported cases each year.
In addition to the morbidity caused by STIs, the burden of STIs also is reflected in the economic costs associated with these infections. These costs comprise direct, indirect, and intangible costs (Chesson et al., 2004). Direct costs are further divided into medical and non medical components. Direct medical costs refer to the expenses of treating acute infections (e.g., diagnostic testing, drug treatments, and doctor visits) and the sequelae of untreated or inadequately treated acute infections, such as pelvic inflammatory disease. Direct non medical costs are those associated with receiving medical treatment, such as transportation to a medical appointment. Indirect costs refer to productivity losses, or lost wages, attributable to STIs. Finally, intangible costs are related to the pain and suffering associated with STIs.
The national direct medical cost of the estimated 9.1 million cases of STIs among young persons aged 15 to 24 years was estimated at $6.5 billion for the year 2000 (Chesson et al., 2004). The bulk of this cost was associated with HIV and HPV infection. Estimates of direct nonmedical, indirect, and intangible costs either do not exist or have not been calculated for all STIs or age-specific groups.
National estimates of incidence and costs of STIs among young persons are important for national policy development and funding decisions on efforts to prevent STIs (Weinstock et al., 2004). National estimates, however, have limited value for states’ and counties’ policy, program, and budgetary decisions, as different states have different population profiles for STI risk. The purpose of this study was to estimate the incidence and direct medical cost of STIs among young persons for California and each of its 58 counties, extending the national estimates and the methodology developed by Weinstock et al. (2004) and Chesson et al. (2004). The estimated incidence and direct medical cost can be used to inform discussions about statewide policies and local resources needed for STI prevention and control efforts.
Healthy for Life Program
Healthy for Life is a program that aims to reduce the rates of overweight and obesity among children and adolescents. It accomplishes this by empowering students with knowledge and tools that aid them in making healthier lifestyle choices. The purpose of this study was to evaluate how effective the program was at achieving its goal. We hypothesized that there would be a significant difference between pre and post BMI, Rosenberg self-esteem scores, and eating and activity behaviors for participants. Results confirmed these hypotheses. Mean BMI for all students regardless of educational level increased significantly; which is to be expected since the participants were still developing phy-siologically. Students who were categorized as overweight or obese, however, did significantly reduce their BMI. Self-esteem is vital in children’s development and previous research has suggested that obesity may interfere with children experiencing feelings of self-worth (Robinson, 2006; Puhl & Latner, 2007). One of the key measures in Healthy for Life is the Rosenberg self-esteem scale. Findings indicate that on average, students significantly improved their self-esteem over the course of the school year. In terms of lifestyle behaviors, preschool and elementary students made healthier food and activity choices at the end of the school year compared to the initial assessment as measured by the picture scale activity.
Participants also showed improvement in other behaviors including exercise six or more times weekly, minimizing junk food intake to two times or less weekly, and including milk in their diet or decreasing the consumption of whole milk. The proportion of students who reported eating breakfast six or more times a week significantly decreased during the school year. Although not statistically significant, findings suggest that students adopted healthier lifestyles in terms of the weekly consumption of fruits and vegetables, fast/restaurant food, and milk.
School-based obesity interventions focusing on healthy eating and physical activity provide an opportunity to improve the health of children since most children in the United States are enrolled in school. However, a limited number of studies have been conducted, results have been variable, and few school-based interventions have demonstrated significant reductions in participant BMI. Since the causal pathways of obesity are so multifaceted, additional support from home, community, policy change, and healthcare environments are necessary to support children’s learned behavior from school-based obesity interventions.
Limitations
Although this study reports significant findings, it is not without weaknesses. Causal inferences could not be made due to the study design. Furthermore, the results from the lifestyle questionnaire used in the program were obtained through self-report, thus validity and reliability could not be assessed, which may have led to some biases.
Physical Activity and Statistical Analysis
Physical Activity
One question was asked to assess physical activity, “how many days per week do you participate for 60 minutes or more in physical activity (walking, biking, running, sports)?” Three answer choices were provided: 0-2 days, 3-5 days, and six or more days. As with the previous variables, responses were collapsed into two categories to assess the students who responded six or more days, the more favorable behavior.
The second questionnaire used in the program, the Rosenberg Self-Esteem Scale, evaluated participants’ self-esteem. The scale has been found to have high reliability; the statistically significant test-retest correlations are typically in the range of .82 to .88 and Cronbach's alpha are in the range of .77 to .88 (Blascovich & Tomaka, 1993; Rosenberg, 1986). The ten-item scale was administered to middle and high school students at the beginning and end of the school year. The answers to the questions are on a four-point Likert scale with the sums from all items equaling the score for that participant. Possible scores range from 0 to 30 with scores below 15 indicating low self-esteem.
The third questionnaire was used specifically for the preschool and elementary students. The tool was developed and validated by Calfas, Sallis, and Nader (1991) for use with children aged 4-8 years to measure their knowledge of healthy food and physical activity behaviors. The activity was conducted by staff at the initial and year-end assessments. The children were presented with 12 photo-pairs; one was a healthy food or activity and the other was not. The sum from all items is the score for that student. Possible scores ranged from 0 to 12.
Statistical Analysis
All statistical analyses were conducted using SPSS version 17.0 (SPSS Inc, Chicago, IL). Descriptive statistics included means and standard deviations where appropriate. Paired samples t test was used to evaluate the differences between initial and year-end BMI for all students, those at or above the 85th percentile, preschool and elementary students, and middle and high school students. Changes in the Rosenberg self-esteem scores and picture scale activity scores were also evaluated for all students and those categorized as overweight or obese using the paired t test. McNemar test was used to explore the change in proportions of the baseline and year-end lifestyle variables. A significance level of p< .05 was used for all analyses.
Results
During the 2008-2009 school year, 1,469 students enrolled in Healthy for Life. The characteristics of the participants are presented in Table 1. Most of the children were of Hispanic origin (66%) and female (55%). The mean age of the participants was 11.7 years (SD=4.6). The dropout rate during the school year was about 19% (n=280), leaving 1,189 students in the program. Of those who did not participate in the program, 5% (n=14) were discounted by the pediatrician due to health concerns and the remaining 95% (n=266) chose to withdraw. Demographic characteristics of the students who dropped out were studied. They were significantly older than the program
Childhood Obesity. Part 4
In addition to the physiological measurements, three questionnaires were used to assess the students’ lifestyle choices and their self-esteem. The eight-item lifestyle questionnaire used questions from previously validated research and explored screen time, dietary habits, physical activity, and sedentary behaviors (Edmunds & Ziebland, 2002; Francis, Lee, & Birch, 2003; Giammattei, Blix, Hopp Marshak, Wollitzer, & Pettitt, 2003; Kubik, Lytle, & Story, 2005). The tool was administered to middle and high school students and as a proxy measure for the preschool and elementary students, the questionnaire was adapted to the third person for the parents to complete.
Screen Time
Screen time, which includes television viewing, video games, and computer usage, has been shown to be a contributor to decreased physical activity and increased sedentary behavior during leisure time (Francis, Lee, & Birch, 2003). To assess screen time during leisure time the following question was asked, “how many hours per day do you participate in screen time (TV, video games, or computer)?” Three answer choices were provided, “less than two hours,” two hours,” and “more than two hours.” For the purpose of analysis, the response choices were collapsed into two categories to assess the change in the least favorable behavior from baseline to year-end (i.e. greater than two hours versus two hours and less).
Nutrition
Six questions regarding the weekly frequency of vegetable, fruit, breakfast, and milk consumption as well as the frequency of fast\restaurant food were asked. The questions included: “How many days per week do you…eat fast food/at restaurants; eat breakfast; eat junk food (cookies, candy, soda, chips, etc.); drink 2-3 8 oz cups of milk in a day; and eat 5 or more fruits and/or vegetables in a day?” Three answer choices were provided: 0-2 days, 3-5 days, and 6 or more days. In the analysis, the responses to the questions on the consumption of milk, and fruits and vegetables were dichotomized to assess the change from baseline to year-end in those who reported practicing the behavior six or more days (i.e. 6 or more days versus 0-5 days). In the case of the questions assessing junk food and fast/restaurant food intake, the reverse was done (i.e. 0-2 days versus 3-5 and 6 or more days). Participants were also asked the type of milk they consume the most with the following question “please indicate ONE type of milk that you drink most often.” The predetermined answer choices were “whole,” “2% low fat,” “1% low fat,” “nonfat,” “soymilk,” and “none.” Response choices were grouped into two categories in the analysis in order to assess the change in those adopting the more favorable behavior (i.e. 2% low fat, 1% low fat, nonfat, and soymilk, versus whole and none).
Childhood Obesity. Part 3
Participants and Methods of Selection
In the 2008-2009 school year, a convenience sample of 51 schools and 1,469 students enrolled in Healthy for Life. Twenty of these schools were Title 1 schools; which are schools where 40% of enrollment consists of children from low-income families (U.S. Department of Education, 2009). Middle and high school students were invited by school staff to join the program. For preschool and elementary students and those in middle and high school who chose to participate, parental notification and active consent were required and a parent information meeting was held before the start of the program.
Procedure
At the beginning of the school year PE teachers underwent training in order to facilitate the curriculum. Middle and high school teachers received four hours of training while preschool and elementary school teachers received six hours. The training was led by instructors who were certified in the respective curriculums (i.e. SPARK and Fitness for Life) and a master PE teacher who demonstrated and educated about the physical activity component of the program. Prosper, M.H., Moczulski V.L., Qureshi, A., Weiss,M., & Bryars,T. / Californian Journal of Health Promotion 2009, Volume 7, Special Issue (Obesity Prevention)
The program participants were assessed three times over the course of the school year. The assessments occurred before the start of the program, at midyear, and at year-end. Registered dieticians collected anthropometric data based on a standard protocol. Height was measured with a stadiometer without shoes and was reported in centimeters. Weight was determined with a calibrated digital scale and was measured in kilograms. Body mass index (BMI) calculations were based on the CDC’s BMI-for-age growth charts for boys and girls. Weight classifications for BMI were defined as underweight <5th percentile; normal weight, 5th to <85th percentile; overweight, 85th to <95th percentile; and obese, ≥95th percentile (CDC, 2009). Overweight and obese students were combined for the purpose of analyses.
A board certified pediatrician conducted a screening physical on each student at the initial assessment and only students who were granted clearance from the pediatrician were eligible to participate in the program. The physician measured the participants’ blood pressure and screened them for skin striae (stretch marks) and Acanthosis Nigricans, an early indicator of insulin resistance that is characterized by hyperpigmentation in areas such as skin folds of the abdomen and the back of the neck (Stuart et al., 1998). Blood pressure was measured on middle and high school students at the initial assessment and only those found to have elevated blood pressure for age, gender and height (≥95th percentile) were reassessed at midyear and year-end. Blood pressure was assessed using a standard blood pressure cuff and stethoscope. Child, adult and large size cuffs were available and the appropriate size was utilized as needed. Students found to have serious medical concerns were referred to their family doctor. If the student did not have a primary care physician a medical home was found for him/her. A medical home is a health care setting that provides comprehensive primary care (American Academy of Family Physicians, American Academy of Pediatrics, American College of Physicians, and American Osteopathic Association, 2007). Follow-up phone contact was initiated with the families toassure medical assessments took place.