2005 Diabetes in California Counties: Prevalence, Risk Factors and Resources

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This report is about Diabetes in California Counties. Its purpose is to provide background information and facts about diabetes. In California, diabetes data is not captured in one statewide registry. Therefore, we have used data collected from the 2001 California Health Interview Survey (CHIS) and compiled a summary of information for each county. CHIS 2001 is currently the best data source for the content of this report in terms of county level information, sub-population analyses, and diabetes indicators. 

We hope that groups like county health departments, community-based organizations and those providing clinical services can use this information to make strategic decisions about their current and future activities. We also hope that environmental planners, industry partners, the media, restaurants, schools, parks and recreation services, and many other groups use these data to inform their work and begin to shift much needed attention to improving health by creating the conditions in which people can be healthy. This paradigm shift will take hard work, cooperation and coordination amongst many.   

The diabetes prevalence and risk factors statistics included in this report are based on the 2001 California Health Interview Survey (CHIS). CHIS is a collaborative project of the University of California, Los Angeles (UCLA) Center for Health Policy Research, the California Department of Health Services, and the Public Health Institute. The first CHIS survey was conducted in 2001 and collected information from more than 55,000 households. In contrast, the CHIS 2003 survey collected information from 42,000 households and omitted two important diabetes indicators from its adult questionnaire, A1C tests and foot exams. The California Diabetes Program determined that the CHIS 2001 is a more appropriate data source for the content of this report and level of sub-population analyses. Only adult data are used in this report because CHIS 2001 does not provide diabetes prevalence and risk factor data at the county level in children and adolescents.

All indicators used in this report from the CHIS survey are self-reported. Diabetes and related risk factor indicators used in this report include:

• Diabetes prevalence
• Persons with diabetes receiving A1C tests and foot exams
• Persons who are overweight or obese, do not participate in regular physical activity, consume less than five servings of fruits and vegetables a day.

These indicators are Healthy People 2010 objectives, and A1C tests and foot exams are also Diabetes National Objectives from the CDC.

Diabetes Prevalence in the report measures the population of adults with diagnosed diabetes. The CHIS survey does not include gestational diabetes. In addition, the National Health and Nutrition Examination Survey (NHANES) has shown that about 25% of people with diabetes in the United States are undiagnosed. Therefore, the actual diabetes prevalence in California counties could be much higher.

A1C Test data measure the population of adults with diabetes who had at least one A1C test during the past 12 months. The A1C test shows the average amount of blood glucose (sugar) over the last 3 months. The findings of major diabetes studies have shown that lowering the A1C level can delay or prevent the development of serious eye, kidney, and nerve disease in people with diabetes.

Foot Exams data measure the population of adults with diabetes who had at least one foot exam by a health professional during the past 12 months. Diabetes is the major cause of non-traumatic lower-limb amputation in the United States. Estimates predict that many of these amputations can be prevented with proper foot care. Simple techniques, such as identification of patients at risk for foot problems and careful monitoring on a regular basis along with education of patients about proper foot care and glucose control, are keys to reducing or preventing foot complications.

Overweight data measure the population of adults with a Body Mass Index (BMI) greater than or equal to 25. Obese data measure the population of adult people with a BMI greater than or equal to 30. BMI is the ratio of weight (kg) and square of height (m²). Studies have shown that people who are overweight are at much greater risk of developing type 2 diabetes and cardiovascular disease than normal weight individuals. Most of people with type 2 diabetes are overweight. The Diabetes Prevention Program (DPP) study has found that lifestyle changes resulting in modest weight loss of 5-7% can prevent or delay the development of type 2 diabetes among adults with pre-diabetes by 58%.

Non-Regular Activity data (also referred to as Physical Inactivity in this report) measure the population of adults who do not meet the current standards for regular physical activity. Regular physical activity refers to those participating in (1) vigorous activity that causes heavy sweating or a large increase in breathing or heart rate for at least 20 minutes three or more times a week, or (2) participating in moderate activity that causes only light sweating or a slight to moderate increase in breathing or heart rate for at least 30 minutes five or more times per week. Physical activity is an important health behavior for people with diabetes as it promotes good health and improves diabetes-related outcomes. In those with pre-diabetes the DPP showed that increasing moderate physical activity by 30 minutes a day for at least 5 days a week coupled with a 5-7% reduction in body weight produced a 58% reduction in the onset of diabetes.

Less-than 5-A-Day data measure the population of adults consuming less than five servings of fruits and vegetables per day. Studies have shown that a diet rich in fruits and vegetables may protect against the development of several chronic diseases and contributes to a healthy weight. For those with diabetes it is important to have a personalized meal plan that includes consumption of fruits and vegetables.  

County and Sub-Population

In this report, data on diabetes prevalence and risk factors are reported for the state, by county, and by age, race and gender sub-populations within each county. The county of residence, age, race and gender from the imputed data are used in this report for the county and sub-population analyses. Smaller population counties are aggregated to obtain reliable statistical estimates. The aggregated counties are grouped as follows:

• Nevada, Plumas, and Sierra
• Alpine, Amador, Calaveras, Inyo, Mariposa, Mono, and Tuolumne
• Del Norte and Humboldt
• Lassen, Modoc, Siskiyou, and Trinity
• Lake and Mendocino
• Monterey and San Benito
• Colusa, Glenn, and Tehama
• Sutter and Yuba

Race sub-groups used in the sub-population analyses include Latino, Asian American (Asian Amer), African American (African Amer), White, and Other based on the California Department of Finance (DOF) race category definition. Specifically, in this report the Latino category is the same as the Latino category by DOF. The White category is the same as the Non-Latino White category by DOF. The Other category is the combination of Pacific Islanders, Multiple Races, and Non-Latino Other categories by DOF. The aggregation of the race/ethnic groups in the Other category used in this report is based on sample size considerations at the county level.

Age sub-groups used in the sub-population analyses are 18-45, 46-64 and 65+ years of age. The selection of these age sub-groups was done to balance the interest in age specific groups (i.e. older adults) with sample size considerations.