Cam Solomon

Inflammatory and Prothrombotic Markers and the Progression of Renal Disease in Elderly Individuals

Inflammatory and prothrombotic markers are elevated in individuals with mild to moderate renal disease. It was hypothesized that these markers may also be determinants of the progression of renal disease. The association of six markers-serum C-reactive protein (CRP), white blood cell (WBC) count, fibrinogen, factor VII, albumin, and hemoglobin-with subsequent elevations of creatinine and decline in estimated GFR in the Cardiovascular Health Study, a community-based cohort of elderly individuals, was analyzed. Linear regression was used to determine predictors of an annualized change in serum creatinine as the main outcome. Duration of follow-up was 7 yr for the original cohort and 4 yr for the more recently recruited black cohort. A total of 588 (12.7%) individuals had a decline in estimated GFR of at least 3 ml/min per yr per 1.73 m(2). Higher CRP (P < 0.001), WBC count (P < 0.001), fibrinogen (P < 0.001), and factor VII (P < 0.001) levels and lower albumin (P < 0.001) and hemoglobin levels (P < 0.001) were associated with a rise in creatinine, after adjusting for age. With additional adjustments for race, gender, baseline creatinine, systolic and diastolic BP, lipid levels, weight, and pack-years smoking, higher CRP, factor VII, fibrinogen, WBC count, and lower albumin and hemoglobin levels remained associated with a rise in creatinine. Similar results were found for decline in estimated GFR. The decline in GFR was greater with increasing number of inflammatory or prothrombotic markers that were above the median (below for hemoglobin and albumin). Inflammatory and prothrombotic markers are predictors for a change in kidney function in elderly individuals. Interventions that reduce inflammation might confer significant cardiovascular and renal benefits.

Pesticide take-home pathway among children of agricultural workers: Study design, methods, and baseline findings

Farmworkers are exposed to pesticides and may take home pesticide residues to their families. In this paper, self-reported pesticide exposure and home practices to reduce the amount of pesticide residues taken home were examined among 571 farmworkers. Urine samples from a subsample of farmworkers and children and dust samples from households and vehicles also assessed pesticide exposure. Overall, 96% of respondents reported exposure to pesticides at work. Many employers did not provide resources for hand washing. Farmworkers’ protective practices to keep pesticide residues out of the home were at a low level. In a subset of respondents, pesticide levels above the limit of quantitation were seen in the urine of children and adults and in house and vehicle dust. The results support the take-home pathway of pesticide exposure. Ways must be found to reduce this pesticide exposure among children of farmworkers.

Melanoma risk in relation to height, weight, and exercise (United States).

Height and weight and derivations thereof are positively associated with a number of cancers. While several authors have reported an increased risk of melanoma among people at the higher extremes of these measures, the association has not been fully explored. New cases of primary cutaneous melanoma in 1997 in western Washington State (n = 386) were compared to controls selected by random-digit dialing (n = 727). Each study participant completed a telephone survey, and data were collected on height, weight, sun-related melanoma risk factors, demographic characteristics, as well as habits such as diet and exercise. Risk of melanoma was analyzed by logistic regression with adjustment for age, hair color, lifetime sun exposure, and fruit and vegetable intake. An excess risk of melanoma was identified in men in the upper quartiles of height (OR = 2.4, 95% confidence interval (CI) = 1.3–4.5), weight (OR = 2.8, CI = 1.5–5.2), and body surface area (OR = 2.8, CI = 1.5–5.1) vs. the lowest quartiles. In women, no association was present for any anthropometric measure. In addition, we found that men and women exercising five to seven days per week were at a decreased risk of melanoma (OR = 0.7, CI = 0.5–1.0). The anthropometric findings are largely consistent with previous studies, while this is the first report of an association of exercise with melanoma risk. The mechanisms for the effect of exercise and for the difference between men and women in the effect of anthropometric factors are unknown. Future research in basic and epidemiologic science should focus on biochemical or behavioral explanations for these observations.

Cancer prevention behaviors and socioeconomic status among Hispanics and non-Hispanic whites in a rural population in the United States.

OBJECTIVES: Socioeconomic status is explored as a predictor of differences between Hispanics and non-Hispanic Whites in cancer prevention behavior.METHODS: In a cross-sectional study, in-person interviews (n = 1795) were conducted in a population-based random sample of adults in 20 communities with a high proportion of Hispanics.RESULTS: Hispanics were significantly less likely than non-Hispanic Whites to ever have had cervical (p < 0.001), breast (p = 0.007), or colorectal cancer (FOBT p = 0.008; sigmoidoscopy/colonoscopy p < 0.002) screening. After adjusting for socioeconomic status (education and having health insurance), only differences in cervical cancer remained significant (p = 0.024). After adjusting for socioeconomic status, Hispanics had a significantly higher intake of fruits and vegetables per day (4.84 servings) than non-Hispanic Whites (3.84 servings) (p < 0.001); and fat behavior score was marginally significant after adjustment for socioeconomic status (p = 0.053). Significantly fewer Hispanics were current smokers than non-Hispanic Whites (p < 0.001).CONCLUSIONS: There is only limited support for the hypothesis that socioeconomic status is a major determinant of some cancer-related behaviors; specifically, socioeconomic status is related to mammography and colorectal screening, but not cervical cancer, dietary behavior, or smoking.

Melanoma and lifetime UV radiation

ObjectiveBecause most risk factors for melanoma are immutable constitutional factors such as skin type, it is important to more fully understand the relationship between melanoma risk and sun exposure, one of the few modifiable risk factors for the disease. The goal of this case–control study was to quantify the risks of melanoma associated with UV exposure at different periods of life. Methods: Cases were 386 patients between the ages of 35 and 74 who were diagnosed with primary cutaneous melanoma within the Seattle–Puget Sound area during 1997. Controls were 727 participants of the same age and geographic area, selected by random-digit dialing. A telephone interview included a complete residential history, lifetime sun exposure history (days in the summer sun for at least 4h at each place of residence), and personal characteristics. UV exposure was calculated based on satellite data on potential erythemal exposure at each place of residence, years at each location and time spent in the sun at each location. Logistic regression was used to estimate odds ratios (OR) and 95 confidence intervals (CI) reflecting the risk of melanoma associated with UV exposure, after adjustment for age, sex, income, tendency to burn and sunburns during ages 2–10. Results: Among women, lifetime UV exposure was associated with melanoma risk (adjusted OR=1.99 for highest versus lowest quartile, 95 CI: 0.95–3.03, p for trend=0.008). There were significant trends for UV exposure during ages 1–10, 11–20 and 31–40 (all p<0.02). Among men, there were no significant associations at any time period, but lifetime UV exposure was associated with higher risk for men who had a tendency toward severe or painful sunburns (OR= 2.85 for highest versus lowest quartile, 95 CI: 0.84–9.64, p for trend=0.04). Conclusion: The differing results by sex are not easily interpretable, though it may be useful to target those with a higher sensitivity to the sun when formulating messages for prevention of melanoma by lowering exposure to UV.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) and risk of cardiovascular disease in older adults: Results from the Cardiovascular Health Study

OBJECTIVE To examine associations between lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) antigen level (mass) and enzymatic activity (activity) and cardiovascular disease (CVD) in older adults. METHODS We examined associations of Lp-PLA(2) mass and activity with incident myocardial infarction (MI; n=508), stroke (n=565) and CVD death (n=665) using Cox regressions adjusted for age, sex, ethnicity and CVD risk factors in 3949 older adults, aged > or =65 years at baseline, from the Cardiovascular Health Study (CHS). RESULTS Lp-PLA(2) was associated with incident CVD events in these older adults. Hazard ratios (95% confidence intervals) for highest versus lowest tertiles of Lp-PLA(2) mass were 1.49 (1.19-1.85) for MI, 1.21 (0.98-1.49) for stroke and 1.11 (0.92-1.33) for CVD death. The highest tertile of Lp-PLA(2) activity was associated with MI (1.36; 1.09-1.70) and CVD death (1.23; 1.02-1.50). Combined Lp-PLA(2) tertile 3 and CRP>3mg/l, compared to Lp-PLA(2) tertile 1 and CRP<1mg/l, was associated with MI (2.29; 1.49-3.52) for Lp-PLA(2) mass and MI (1.66; 1.10-2.51) and CVD death (1.57; 1.08-2.26) for activity. For MI, both mass and activity added excess risk to elevated CRP alone ( approximately 20% excess risk) and activity added excess risk for CVD death ( approximately 12%). CONCLUSION Lp-PLA(2) mass and activity were associated with incident CVD events in older adults in CHS. Lp-PLA(2) and CRP were independent and additive in prediction of events. While associations were modest, these results support further exploration of Lp-PLA(2) to identify older individuals at risk for CVD.

Identifying Persons at Highest Risk of Melanoma Using Self-Assessed Risk Factors.

OBJECTIVE: To develop a self-assessed melanoma risk score to identify high-risk persons for screening METHODS: We used data from a 1997 melanoma case-control study from Washington State, USA, where 386 cases with invasive cutaneous melanoma and 727 controls were interviewed by telephone. A logistic regression prediction model was developed on 75% of the data and validated in the remaining 25% by calculating the area under the receiver operating characteristic curve (AUC), a measure of predictive accuracy from 0.5-1 (higher scores indicating better prediction). A risk score was calculated for each individual, and sensitivities for various risk cutoffs were calculated. RESULTS: The final model included sex, age, hair color, density of freckles, number of severe sunburns in childhood and adolescence, number of raised moles on the arms, and history of non-melanoma skin cancer. The area under the receiver operating characteristic curve(AUC) was 0.70 (95% CI: 0.64, 0.77). The top 15% risk group included 50% of melanomas (sensitivity 50%). CONCLUSIONS: This self-assessed score could be used as part of a comprehensive melanoma screening and public education program to identify high-risk individuals in the general population. This study suggests it may be possible to capture a large proportion of melanomas by screening a small high-risk group. Further study is needed to determine the costs, feasibility, and risks of this approach.

Incident physical disability in people with lower extremity peripheral arterial disease: the role of cardiovascular disease.

OBJECTIVES: To evaluate the risk of incident physical disability and the decline in gait speed over a 6‐year follow‐up associated with a low ankle‐arm index (AAI) in older adults.

Lipoprotein-associated phospholipase A(2) and risk of congestive heart failure in older adults: the Cardiovascular Health Study.

Background—Inflammation may be a causative factor in congestive heart failure (CHF). Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammation marker associated with vascular risk. One previous study showed an association of Lp-PLA2 activity with CHF risk, but there were only 94 CHF cases and Lp-PLA2 antigen, which is available clinically in the United States, was not measured. Methods and Results—We measured baseline Lp-PLA2 antigen and activity in 3991 men and women without baseline CHF or cardiovascular disease who were participating in the Cardiovascular Health Study, a prospective observational study of adults 65 years or older. Cox proportional hazards models adjusted for age, sex, clinic site, race, low-density and high-density lipoprotein cholesterol, body mass index, systolic and diastolic blood pressure, hypertension, smoking status, pack-years, and diabetes were used to calculate hazard ratios and 95% CIs for incident CHF. Further models adjusted for coronary disease events during follow-up and C-reactive protein. Eight hundred twenty-nine participants developed CHF during 12.1 years. Adjusted hazard ratios for CHF with Lp-PLA2 in the fourth compared with the first quartile were 1.44 (95% CI, 1.16 to 1.79) for Lp-PLA2 antigen and 1.06 (95% CI, 0.84 to 1.32) for activity. Adjustment for incident coronary disease attenuated the hazard ratio for Lp-PLA2 antigen to 1.26 (95% CI, 1.02 to 1.57), adjustment for C-reactive protein had minimal impact. Conclusions—Lp-PLA2 antigen was associated with risk of future CHF in older people, independent of CHF and coronary risk factors, and partly mediated by coronary disease events. Further clinical and basic research is needed to better understand the role of Lp-PLA2 in CHF.

Lipoprotein-Associated Phospholipase A2 and Risk of Congestive Heart Failure in Older AdultsCLINICAL PERSPECTIVE

Background—Inflammation may be a causative factor in congestive heart failure (CHF). Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammation marker associated with vascular risk. One previous study showed an association of Lp-PLA2 activity with CHF risk, but there were only 94 CHF cases and Lp-PLA2 antigen, which is available clinically in the United States, was not measured. Methods and Results—We measured baseline Lp-PLA2 antigen and activity in 3991 men and women without baseline CHF or cardiovascular disease who were participating in the Cardiovascular Health Study, a prospective observational study of adults 65 years or older. Cox proportional hazards models adjusted for age, sex, clinic site, race, low-density and high-density lipoprotein cholesterol, body mass index, systolic and diastolic blood pressure, hypertension, smoking status, pack-years, and diabetes were used to calculate hazard ratios and 95% CIs for incident CHF. Further models adjusted for coronary disease events during follow-up and C-reactive protein. Eight hundred twenty-nine participants developed CHF during 12.1 years. Adjusted hazard ratios for CHF with Lp-PLA2 in the fourth compared with the first quartile were 1.44 (95% CI, 1.16 to 1.79) for Lp-PLA2 antigen and 1.06 (95% CI, 0.84 to 1.32) for activity. Adjustment for incident coronary disease attenuated the hazard ratio for Lp-PLA2 antigen to 1.26 (95% CI, 1.02 to 1.57), adjustment for C-reactive protein had minimal impact. Conclusions—Lp-PLA2 antigen was associated with risk of future CHF in older people, independent of CHF and coronary risk factors, and partly mediated by coronary disease events. Further clinical and basic research is needed to better understand the role of Lp-PLA2 in CHF.