Craig A. Molgaard

ALS and heavy metals A pilot case‐control study

We conducted a case-control study of suspected risk factors for ALS among referral patients seen at the Mayo Clinic. Responses to questions about demographic factors, diet, medical history, travel, infectious disease, and other variables were similar in ALS patients and controls. In all but a few items, the responses of the cases and controls did not differ significantly. A significant level of shared exposure to an exogenous agent or environmental insult among cases was noted mainly for heavy metals.

Generic Tobacco Use among Four Ethnic Groups in a School Age Population

The prevalence of overall or “generic” tobacco use among Hispanic, white, Black and Asian youths in grades four, seven, ten and twelve was compared in San Diego, California (n = 4980). Significant differences in generic tobacco use between ethnic groups were found in the 4th, 10th and 12th grades, but were greatest in the 10th grade. Only white youths demonstrated a sharp increase in regular tobacco use (once a month or more) between 7th and 10th grade. Overall, the prevalence of regular use was highest among whites (25.8%), followed by Hispanics (19.7%), Blacks (17.6%) and Asians (12.6%). Marijuana, alcohol, and other drug use explained approximately 40 percent of the variance in tobacco use in each ethnic group. Other predictors varied by ethnicity and included socioeconomic status, happiness of student, strictness of parent, adult tobacco use at home, accessibility to marijuana, and gender.

Amyotrophic Lateral Sclerosis and Occupational Heavy Metal Exposure: A Case-Control Study

A retrospective case-control study of occupational heavy metal exposure was conducted using 66 amyotrophic lateral sclerosis (ALS) patients and 66 age- and sex-matched controls. Cases were ascertained primarily through a neurology support and research clinic. The self-administered questionnaire probed potential exposure to nine heavy metals: aluminum, lead, lead alkyl, magnesium, manganese, mercury, mercury alkyl, nickel and selenium. Using McNemars test and a Mantel Haenszel extended analysis, no association was found between heavy metal exposure and the pathogenesis of ALS in this patient population. Demographic factors, fracture history, immunizations, travel and other variables were similar in ALS patients and controls.

Migraine trigger factors in a non‐clinical Mexican‐American population in San Diego county: implications for etiology

We conducted an investigation of migraine headache in a general population of Mexican-Americans living in San Diego county. Specific headache triggers were reported and analyzed, the most frequently reported for females with migraine being missing meals (58.9%), weather changes (54.4%), menstruation (53.6%), post-crisis letdown (52.7%), and fatigue (51.8%). The most frequently reported trigger factors for migraines reported by males were fatigue (58.8%), sleep (as a precipitating factor) (56.3%), post-crisis letdown (41.2%), and weather changes (37.5%). Trigger factors were further evaluated using stratification by presence or absence of Raynauds phenomenon (RP), menstrual migraine, family history of migraine, and by migraine type. Odds ratios and 95% confidence intervals were calculated. These results suggest that subjects with migraine and RP (perhaps indicative of a systematic vascular tone disorder) and those with menstrual migraine (indicative of sensitivity to hormonal changes) may overall be more sensitive to certain environmental stimuli, particularly those involving change in the internal environment.

Prevalence of alcohol consumption among older persons

Percent prevalences of alcohol consumption were determined in a cross-sectional study of randomly chosen residents of San Diego County, California aged 45 years and over. The study sample (N=2,105) showed statistically significant drinking differences between Whites (n=819), Blacks (n=629), and Mexican-Americans (n=657). Overall, the highest prevalence of drinking occurred among the White elderly. The common belief that socioeconomic conditions are inversely associated with a high prevalence of drinking was not supported in this sample. Statistically significant differences in age-specific and sex-specific percent prevalences of alcohol intake were also found. There was a generally decreasing prevalence of alcohol consumption with advancing age, which existed regardless of ethnicity. Initial empirical measures and a better understanding of drinking correlates will identify those elderly persons at risk and provide the basis for future interventions in the areas of applied epidemiology and health promotion.

Cholinesterase and Self-reported Pesticide Exposure among Pregnant Women

Ascertainment of exposure to cholinesterase-inhibiting pesticides in pregnant subjects is complicated by altered enzyme activity that results from metabolic changes associated with pregnancy. Nevertheless, this study found a high correlation (Pearson chi-square = 13.67, p = .008) between classification of pesticide exposure using self-reported interview information and plasma cholinesterase activity for 203 pregnant women for whom three trimester cholinesterase values were available. All plasma cholinesterase activity values were referenced, by trimester, to a larger sample of 1,050 plasma cholinesterase values from 535 pregnant women. Subjects who lived nearest to agricultural land and who reported that they worked with pesticides in agricultural and other occupations tended to have lower plasma cholinesterase activity than those who reported use of household pesticides only.

Amyotrophic lateral sclerosis and history of skeletal fracture A case‐control study

A retrospective case-control study was conducted, using 66 amyotrophic lateral sclerosis (ALS) patients and 66 closely matched controls. Cases were ascertained primarily through a neurology clinic. A self-administered questionnaire probed for history of skeletal fractures. Using McNemars test, no association was found between history of skeletal fracture and pathogenesis of ALS. No predilection for the head, neck, or spine was demonstrated. The extremities accounted for most fracture sites in cases and controls. Among cases, 68% of the fractures occurred before diagnosis, 58% occurring more than 10 years before diagnosis of ALS.

The Association between Cerebrovascular Disease and Smoking: A Case-Control Study

A retrospective case-control study was carried out to examine the relationship between cigarette smoking and cerebrovascular disease occurrence. Cases were obtained from the University of California-American Heart Association, San Diego Stroke Data Bank, and controls from selected Veterans Administration and University of California, San Diego, outpatient departments. When cigarette smoking was dichotomously coded into categories of low and high lifetime exposure, consistent significant positive associations were found with cerebrovascular disease occurrence in both bivariate and multivariate analysis when controlling for blood pressure. These associations, however, were not found when smoking was categorized as smoker, ex-smoker, and non-smoker. No association was found between passive smoking and cerebrovascular disease. The results indicate that a cumulative lifetime exposure to active cigarette smoking is directly associated with cerebrovascular disease.

Breast cancer histology in Caucasians, African Americans, Hispanics, Asians, and Pacific Islanders.

STUDY OBJECTIVES To investigate the association between race/ethnicity and histologic types of breast cancer. DESIGN Cross-sectional study. SETTING Population-based data from the Northern California Tumor Registry, which is part of the National Cancer Institutes Surveillance, Epidemiology and End Results Program. PARTICIPANTS A total of 2759 breast cancer cases diagnosed in 1988. MAIN RESULTS Tumors were classified as ductal, lobular, and mixed/unspecified carcinoma. Ductal carcinoma was the most common (83.6%) and lobular carcinoma was the rarest. Most cases were diagnosed in the localized stage (56.3%). Caucasian women had the highest rates of total breast cancer (240.9/100,000), ductal and lobular. In African-American women, the odds of ductal carcinoma were twice that of lobular carcinoma, compared with Caucasian women (odds ratio [OR] = 2.0, 95% confidence interval [CI] 1.0-3.9) after adjusting for age, site, and stage at diagnosis. Similarly, Asian and Hispanic women also had higher, non-statistically significant odds of ductal versus lobular carcinoma compared with Caucasians (OR = 1.8 [95% CI 0.9-3.7] and 1.6 [95% CI 0.8-3.4], respectively). CONCLUSIONS Future studies should investigate how racial/ethnic differences in histology among breast cancer patients will influence life expectancy, against a backdrop of health care access, sociocultural issues, lifestyle habits, reproductive history, family history, and tumor characteristics.

Lack of Association of Swine Flu Vaccine and Rheumatoid Arthritis

On the basis of available incidence rates, about 22,000 new cases of definite rheumatoid arthritis would have developed fortuitously among the 45 million recipients of the swine flu vaccine during the year after the immunization program. No excess has been detected. Proportional morbidity studies among all Mayo Clinic patients and among the active-duty personnel of the US Army showed no increase in the number of cases of rheumatoid arthritis after administration of the swine flu vaccine. These results do not support the claims based on anecdotal reports of an association of the vaccine with rheumatoid arthritis.