Measuring wellness among resident physicians

Requirements to include professionalism in residency curricula have generated a substantial body of literature concerning the environments that fail to nurture professionalism. Local and national surveys provide evidence that a high prevalence of depersonalization and emotional exhaustion exists among residents and that clinical practice is impaired as a result of these factors. A group of 34 residents from ten residency programmes participated in the psychometric testing of a resident wellness assessment instrument that can be rapidly administered, scored, and interpreted. The Brief Resident Wellness Profile is composed of a Mood faces graphical rating item and a six-question subscale. The six-item subscale had good reliability (alpha = 0.83; r = 0.84), convergent validity (r = 0.63), discriminant validity (r = -0.37), and concurrent validity ( p = 0.007). The Mood faces item had good convergent validity (r = 0.66), discriminant validity (r = -0.71), and concurrent validity ( p = 0.008). The Brief Resident Wellness Profile appears to be a reliable and valid instrument that measures residents' sense of professional accomplishment and mood and can be rapidly administered, scored, and interpreted.

Thorough skin self-examination in patients with melanoma

PURPOSE/OBJECTIVES

To examine the feasibility of using Weinstock et al.'s thorough skin self-examination (TSSE) assessment in patients with melanoma, to describe TSSE characteristics of patients with melanoma, and to explore associations of personal and disease variables with TSSE.

DESIGN

Cross-sectional, descriptive feasibility study; part of a larger study of melanoma in families.

SETTING

Outpatient melanoma clinics in a National Cancer Institute-designated comprehensive cancer center.

SAMPLE

Purposive sample of 70 predominantly white participants (47% women, 53% men), with a mean age of 65 years (SD = 11 years) and pathologically confirmed cutaneous melanoma (any stage).

METHODS

Weinstock et al.'s TSSE assessment (self-report of the number of times patients examined the surface of seven specific body areas during the prior two months) and items regarding partnered TSSE and skin examination from healthcare providers.

MAIN RESEARCH VARIABLES

Frequency of TSSE and healthcare provider skin examination, partnered TSSE, and reasons for not performing TSSE.

FINDINGS

Forty-one (59%) participants reported performing TSSE; by Weinstock et al.'s criteria, only 23 (33%) practiced TSSE. Use of a partner was significantly associated with TSSE (p = 0.001); patients indicated high rates of skin examination by healthcare providers.

CONCLUSIONS

Patients with melanoma are at high risk for recurrent disease. TSSE contributes to early detection of melanoma. Although Weinstock et al.'s TSSE assessment is feasible for use among patients with melanoma in a clinical setting, the focus should be on examination of specific body areas, rather than global skin examination. Overall, patients with melanoma had a low frequency of TSSE; however, data regarding previous knowledge or instruction of TSSE were not collected. Involving a partner enhances the frequency of TSSE.

IMPLICATIONS FOR NURSING

Patients with melanoma should be informed of the importance of conducting systematic TSSE and using a partner during examination; however, some patients may prefer skin examination by healthcare providers. Measurement of TSSE self-report merits further study.

Fatty acid composition of red blood cell membranes and risk of squamous cell carcinoma of the skin

Differential effects of fatty acids on carcinogenesis suggest that fatty acid composition is important in tumor development. Arachidonic acid and its metabolites elicit inflammation and promote tumor formation in mouse skin. Inhibitors of the arachidonic cascade inhibit tumor incidence. A population-based case control study in Southeastern Arizona tested the hypothesis that lower levels of arachidonic acid in RBC membranes were associated with decreased risk of skin squamous cell carcinoma (SCC; n = 335 SCC cases and 321 controls). Extracted and esterified RBC fatty acids were analyzed using capillary gas chromatography. Individual peaks for 14 fatty acids were measured as a percentage of total fatty acids. Logistic regression was used to estimate odds ratios (OR), adjusting for SCC risk factors (age, gender, actinic keratosis history, freckling, and tanning ability). Increased levels of arachidonic acid in RBC membranes were associated with increased risk of SCC [odds ratio (OR), 1.08 per mg/100 mL change; 95% confidence interval (95% CI), 1.02-1.15] and this association remained when controls with actinic keratosis precursor lesions were excluded. SCC risk was highest among the upper quartile of arachidonic acid (OR, 2.38; 95% CI, 1.37-4.12). In contrast, increasing proportions of palmitic acid (OR, 0.94; 95% CI, 0.89-1.00) and palmitoleicacid (OR, 0.49; 95% CI, 0.30-0.81) were associated with reduced SCC risk. More studies are needed to elucidate the function of RBC fatty acids so that recommendations can be made to alter the human diet for cancer prevention.

A cross-sectional analysis demonstrated the healthy volunteer effect in smokers

OBJECTIVE

This cross-sectional descriptive analysis sought to determine if a healthy volunteer effect can be demonstrated among smokers selected to participate in a dietary intervention trial.

STUDY DESIGN AND SETTING

Body mass index (BMI), body fat, physical activity, dietary intake, and plasma concentration of antioxidant nutrients and carotenoids were assessed cross-sectionally, at the time of enrollment into a dietary intervention trial, among 136 adult smokers.

RESULTS

Mean BMI was below national age- and gender-specific averages as was prevalence of overweight and obesity. Physical activity was reported to average 15.4 h/wk. Compared with other sample populations of smokers, our smokers reported lower total fat and cholesterol intakes, higher vitamin C and beta-carotene intakes, and generally equal vitamin E intakes. Plasma ascorbic acid, alpha-tocopherol, alpha- and beta-carotene, and beta-cryptoxanthin concentrations were higher than those of smokers surveyed by NHANES III.

CONCLUSION

These findings suggest that a "healthy volunteer effect" can be described among adult smokers. Future dietary intervention trials among smokers should cautiously estimate sample size because smokers electing to participate may report healthier dietary patterns than other smokers. Screening criteria regarding baseline micronutrient status of smokers should be evaluated given that intervention effects may be dependent on overall health status.

Effect of a 4-Month Tea Intervention on Oxidative DNA Damage among Heavy Smokers

Glutathione S-transferase (GST), a member of the phase II group of xenobiotic metabolizing enzymes, has been intensively studied at the levels of phenotype and genotype. The GST mu 1 (GSTM1) and GST theta 1 (GSTT1) genes have a null-allele variant in which the entire gene is absent. The null genotype for both enzymes has been associated with many different types of tumors. The aim of this study was to determine the possible differences in increased oxidative stress susceptibility to smoking within the GSTM1 and GSTT1 genotypes and the impact of high tea drinking on this. We designed a Phase II randomized, controlled, three-arm tea intervention trial to study the effect of high consumption (4 cups/day) of decaffeinated green or black tea, or water on oxidative DNA damage, as measured by urinary 8-hydroxydeoxyguanosine (8-OHdG), among heavy smokers over a 4-month period and to evaluate the roles of GSTM1 and GSTT1 genotypes as effect modifiers. A total of 133 heavy smokers (100 females and 33 males) completed the intervention. GSTM1 and GSTT1 genotype statuses were determined with a PCR-based approach. Multiple linear regression models were used to estimate the main effects and interaction effect of green and black tea consumption on creatinine-adjusted urinary 8-OHdG, with or without adjustment for potential confounders. Finally, we studied whether the effect of treatment varied by GSTM1 and GSTT1 status of the individual. Although there were no differences in urinary 8-OHdG between the groups at baseline, the between-group 8-OHdG levels at month 4 were statistically significant for GSTM1-positive smokers (P = 0.05) and GSTT1-positive smokers (P = 0.02). GSTM1-positive and GSTT1-positive smokers consuming green tea showed a decrease in urinary 8-OHdG levels after 4 months. Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed significant effect for green tea consumption (P = 0.001). The change from baseline was significant in both GSTM1-positive (t = -2.99; P = 0.006) and GSTT1-positive (P = 0.004) green tea groups, but not in the GSTM1-negative (P = 0.07) or GSTT1-negative (P = 0.909) green tea groups. Decaffeinated black tea consumption had no effect on urinary 8-OHdG levels among heavy smokers. Our data show that consumption of 4 cups of tea/day is a feasible and safe approach and is associated with a significant decrease in urinary 8-OHdG among green tea consumers after 4 months of consumption. This finding also suggests that green tea intervention may be effective in the subgroup of smokers who are GSTM1 and/or GSTT1 positive.

Effect of Increased Tea Consumption on Oxidative DNA Damage among Smokers: A Randomized Controlled Study

Tea drinking has been associated with decreased occurrence of cancer and heart disease. One potential mechanism for these findings is the strong antioxidant effect of tea polyphenols. A phase II randomized controlled tea intervention trial was designed to study the effect of high consumption (4 cups/d) of decaffeinated green or black tea on oxidative DNA damage as measured by urinary 8-hydroxydeoxyguanosine (8-OHdG) among smokers over a 4-mo period. A total of 143 heavy smokers, aged 18-79 y, were randomized to drink either green or black tea or water. Levels of plasma and urinary catechins and urinary 8-OHdG were measured monthly. A total of 133 of 143 smokers completed the 4-mo intervention. Multiple linear regression models were used to estimate the main effects and interaction effect of green and black tea consumption on creatinine-adjusted urinary 8-OHdG, with or without adjustment for potential confounders. Plasma and urinary levels of catechins rose significantly in the green tea group compared with the other two groups. Assessment of urinary 8-OHdG after adjustment for baseline measurements and other potential confounders revealed a highly significant decrease in urinary 8-OHdG (-31%) after 4 mo of drinking decaffeinated green tea (P = 0.002). No change in urinary 8-OHdG was seen among smokers assigned to the black tea group. These data suggest that regular green tea drinking might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking.

Women physicians are early adopters of on-line continuing medical education

INTRODUCTION

On-line continuing medical education (CME) provides advantages to physicians and to medical educators. Although practicing physicians increasingly use on-line CME to meet their educational needs, the overall use of on-line CME remains limited. There are few data to describe the physicians who use this new educational medium; yet, they clearly are the innovators and early adopters who will facilitate the growth of this educational technology. It would be useful to instructional designers and CME developers to better understand the characteristics of this influential group.

METHODS

We studied the actual use of several different on-line CME programs within three different groups of physicians. The on-line programs were developed as part of research studies funded by the National Institutes of Health, with no relationship to commercial interests. They were presented to physicians using mass mailouts (two physician groups) or personal contact and were accompanied by incentives to reduce resistance to the new technology. We compared the characteristics of physicians who chose to use these on-line programs with demographic data from larger populations representing the groups from which these users originated.

RESULTS

We found that physicians who used these on-line CME programs were younger than average and, importantly, more likely to be female than expected. This finding was consistent across different types of physician populations and different types of CME programs.

DISCUSSION

Based on data reflecting actual use of on-line CME, younger physicians appear to be adopting on-line CME more rapidly than others, and women physicians appear to be adopting on-line CME at a faster rate than their male counterparts. This latter finding conflicts with the impression provided by some survey-based studies that male physicians are more likely than female physicians to use on-line CME. The data suggest that the growth of on-line CME is most likely occurring in diffusion networks dominated by relatively new medical school graduates and, possibly, women physicians. These results provide valuable insight to those who seek to develop and market on-line CME and those who seek to reach women physicians with CME programs.

Weight lifted in strength training predicts bone change in postmenopausal women

PURPOSE

The aim of this study was to examine the relationship between weight lifted in 1 yr of progressive strength training and change in bone mineral density (BMD) in a group of calcium-replete, postmenopausal women.

METHODS

As part of a large clinical trial, 140 calcium-supplemented women, 44-66 yr old, were randomized to a 1-yr progressive strength-training program. Half of the women were using hormone replacement therapy. Three times weekly, subjects completed two sets of six to eight repetitions in eight core exercises at 70-80% of one repetition maximum. BMD was measured at baseline and 1 yr.

RESULTS

In multiple linear regression, the increase in femur trochanter (FT) BMD was positively related to total weight lifted (0.001 g.cm (-2)) for a SD of weight lifted, P< 0.01) after adjusting for age, baseline factors, HRT status, weight change, cohort, and fitness center. The weighted squats showed the strongest (0.002 g.cm(-2)) for a SD of weight lifted, P< 0.001), whereas the back extension exhibited the weakest (0.0005 g.cm(-2)) for a SD of weight lifted, P< 0.26) association with change in FT BMD. The amount of weight lifted in the weighted march exercise was significantly related to total body BMD (0.0006 g.cm(-2)) for a SD of weight lifted, P< 0.01). The associations between weight lifted and BMD for the femur neck or lumbar spine were not significant.

CONCLUSION

Evidence of a linear relationship between BMD change and total and exercise-specific weight lifted in a 1-yr strength-training program reinforces the positive association between this type of exercise and BMD in postmenopausal women.

Vitamin A, carotenoids, and risk of persistent oncogenic human papillomavirus infection

Oncogenic human papillomavirus (HPV) infection is the main etiologic factor for cervical neoplasia, although infection alone is insufficient to produce disease. Cofactors such as nutritional factors may be necessary for viral progression to neoplasia. Results from previous studies have suggested that higher dietary consumption and circulating levels of certain micronutrients may be protective against cervical neoplasia. This study evaluated the role of vitamin A and carotenoids on HPV persistence comparing women with intermittent and persistent infections. As determined by the Hybrid Capture II system, oncogenic HPV infections were assessed at baseline and at approximately 3 and 9 months postbaseline. Multivariate logistic regression analysis was used to determine the risk of persistent HPV infection associated with each tertile of dietary and circulating micronutrients. Higher levels of vegetable consumption were associated with a 54% decrease risk of HPV persistence (adjusted odds ratio, 0.46; 95% confidence interval, 0.21-0.97). Also, a 56% reduction in HPV persistence risk was observed in women with the highest plasma cis-lycopene concentrations compared with women with the lowest plasma cis-lycopene concentrations (adjusted odds ratio, 0.44; 95% confidence interval, 0.19-1.01). These data suggest that vegetable consumption and circulating cis-lycopene may be protective against HPV persistence.

Human papillomavirus persistence and nutrients involved in the methylation pathway among a cohort of young women

Persistent oncogenic human papillomavirus (HPV) infection is associated with cervical dysplasia. Cofactors, such as nutrient status, may be required for the progression of HPV infection to neoplasia. HPV DNA methylation patterns in vitro have been shown to be associated with viral transcriptional activity. Folate, vitamin B12, vitamin B6, and methionine may function to prevent cervical cancer through their role in DNA methylation. This study was conducted to examine the relationship of dietary intake of folate, vitamin B12, vitamin B6, and methionine, as well as circulating levels of folate and vitamin B12 to HPV persistence. Oncogenic HPV status was determined at baseline and at approximately 3 and 9 months postbaseline. Multivariate logistic regression analysis was used to determine the adjusted odds ratios for persistent HPV infection associated with each tertile of individual nutrient among 201 women with a persistent or intermittent HPV infection. Circulating vitamin B12 levels were inversely associated with HPV persistence (P for trend, 0.037) after adjusting for age, age at first intercourse, marital status, cigarette smoking status, race, and body mass index. In addition, women with circulating levels in the highest tertile (>493.2 pg/ml) of vitamin B12 were less likely to have a persistent infection (adjusted odds ratio = 0.4; 95% confidence interval = 0.17-0.96). No significant associations were observed between HPV persistence and dietary intake of folate, vitamin B12, vitamin B6, or methionine from food alone or from food and supplements combined or from circulating folate. These data suggest a role for circulating vitamin B12 in early cervical carcinogenesis.

Citrus peel use is associated with reduced risk of squamous cell carcinoma of the skin

Limonene has demonstrated efficacy in preclinical models of breast and colon cancers. The principal sources of d-limonene are the oils of orange, grapefruit, and lemon. The present case-control study was designed to determine the usual citrus consumption patterns of an older Southwestern population and to then evaluate how this citrus consumption varied with history of squamous cell carcinoma (SCC) of the skin. In this Arizona population, 64.3% and 74.5% of the respondents reported weekly consumption of citrus fruits and citrus juices, respectively. Orange juice (78.5%), orange (74.3%), and grapefruit (65.3%) were the predominant varieties of citrus consumed. Peel consumption was not uncommon, with 34.7% of all subjects reporting citrus peel use. We found no association between the overall consumption of citrus fruits [odds ratio (OR) = 0.99, 95% confidence interval (CI) = 0.73-1.32] or citrus juices (OR = 0.97, 95% CI = 0.71-1.31) and skin SCC. However, the most striking feature was the protection purported by citrus peel consumption (OR = 0.66, 95% CI = 0.45-0.95). Moreover, there was a dose-response relationship between higher citrus peel in the diet and degree of risk lowering. This is the first study to explore the relationship between citrus peel consumption and human cancers. Our results show that peel consumption, the major source of dietary d-limonene, is not uncommon and may have a potential protective effect in relation to skin SCC. Further studies with large sample sizes are needed to more completely evaluate the interrelationships between peel intake, bioavailability of d-limonene, and other lifestyle factors.

Trends in the incidence of nonmelanoma skin cancers in southeastern Arizona, 1985-1996

This report describes trends in the incidence of various nonmelanoma skin cancers in a region of high ultraviolet exposure. The Southeastern Arizona Skin Cancer Registry routinely identified cases of skin cancer between 1985 and 1996 through pathology logs and reports from dermatology offices and laboratories in 3 Arizona counties. The incidence rates for squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) for non-Hispanic whites were 3 to 6 times higher than the incidence rates from more northern regions. The rates for non-Hispanic whites were approximately 11 times greater than rates for Hispanics. Furthermore, there was no constant increase in the incidence of nonmelanoma skin cancers. The incidence of SCC, in particular, demonstrated a plateau or even a modest decline between 1985 and 1996. Thus the incidence rates of both SCC and BCC in Arizona, although among the highest in the world, do not appear to be increasing as rapidly as predicted elsewhere.

Joint effects of citrus peel use and black tea intake on the risk of squamous cell carcinoma of the skin

BACKGROUND

Differences in tea drinking habits and/or citrus peel use are likely to vary by populations and could contribute to the inconsistencies found between studies comparing their consumption and cancer risk.

METHODS

A population-based case-control study was used to evaluate the relationships between citrus peel use and black tea intake and squamous cell carcinoma (SCC) of the skin. Moreover, we assessed the independent and interactive effects of citrus peel and black tea in the development of SCC.

RESULTS

Hot and iced teas were consumed by 30.7% and 51.8% of the subjects, respectively. Peel consumption was reported by 34.5% of subjects. Controls were more likely than were cases to report citrus peel use (odds ratio (OR) = 0.67) and hot tea intake (OR = 0.79). After adjustment for hot and iced tea intake, the ORs associated with citrus peel use were 0.55 and 0.69, respectively, whereas the corresponding adjusted ORs for hot and iced tea intake after adjustment for citrus peel use were 0.87 and 1.22 respectively. Compared with those who did not consume hot black tea or citrus peel, the adjusted ORs associated with sole consumption of hot black tea or citrus peel were 0.60 and 0.30, respectively. Subjects who reported consumption of both hot black tea and citrus peel had a significant marked decrease (OR= 0.22; 95% CI = 0.10 - 0.51) risk of skin SCC.

CONCLUSION

These results indicate that both citrus peel use and strong (hot) black tea have independent potential protective effects in relation to skin SCC.

Metabolic responses to leptin in obese db/db mice are strain dependent

Obese, diabetic C57BL/Ks db/db mice that lack the long-form leptin receptor exhibit no decrease in body weight or food intake when treated with leptin. Here we compared responses to leptin in two strains of db/db mice: C57BL/6J mice that are hyperglycemic and hyperinsulinemic and C57BL/Ks that are hyperglycemic and normo- or hypoinsulinemic. Chronic intraperitoneal infusion of 10 microgram leptin/day partially reversed hyperglycemia in C57BL/6J male mice but exaggerated the diabetic state of female mice. Bolus intraperitoneal injections of 40 microgram leptin/day did not effect glucose in either strain of male db/db mice, whereas chronic intraperitoneal infusion of 20 microgram leptin/day significantly reduced fasting blood glucose in male mice from both strains, especially C57BL/6J mice. Food intake, body weight, rectal temperature, and body fat did not change. Chronic intraperitoneal infusion of 10 microgram leptin/day significantly reduced body fat in lean db/+ C57BL/6J but not in C57BL/Ks mice. Thus peripherally administered leptin is active in mice that have only short-form leptin receptors, and the response is dependent on the method of leptin administration and the background strain.

Overexpression of agouti protein and stress responsiveness in mice

Ectopic overexpression of agouti protein, an endogenous antagonist of melanocortin receptors' linked to the beta-actin promoter (BAPa) in mice, produces a phenotype of yellow coat color, Type II diabetes, obesity and increased somatic growth. Spontaneous overexpression of agouti increases stress-induced weight loss. In these experiments, other aspects of stress responsiveness were tested in 12-week-old male wild-type mice and BAPa mice. Two hours of restraint on three consecutive days produced greater increases in corticosterone and post-stress weight loss in BAPa than wild-type mice. In Experiment 2, anxiety-type behavior was measured immediately after 12 min of restraint. This mild stress did not produce many changes indicative of anxiety, but BAPa mice spent more time in the dark side of a light-dark box and less time in the open arms of an elevated plus maze than restrained wild-type mice. In a defensive withdrawal test, grooming was increased by restraint in all mice, but the duration of each event was substantially shorter in BAPa mice, possibly due to direct antagonism of the MC4-R by agouti protein. Thus, BAPa mice showed exaggerated endocrine and energetic responses to restraint stress with small differences in anxiety-type behavior compared with wild-type mice. These results are consistent with observations in other transgenic mice in which the melanocortin system is disrupted, but contrast with reports that acute blockade of central melanocortin receptors inhibits stress-induced hypophagia. Thus, the increased stress responsiveness in BAPa mice may be a developmental compensation for chronic inhibition of melanocortin receptors.

Reproducibility and relative validity of a questionnaire to assess intake of black tea polyphenols in epidemiological studies

Epidemiological studies suggest that tea drinking may reduce the risk of cardiovascular diseases and cancers. Although tea is an important source of antioxidant phytochemicals, variation in preparation techniques may translate to variation in antioxidant capacity. However, most large-scale epidemiological studies use regular food frequency questionnaires to estimate tea intake, and nationally available nutrient analysis databases do not include levels of black tea polyphenols. The Arizona Tea Questionnaire (ATQ) was designed as a tool for collecting more complete dietary tea consumption information, and a database was developed after analyzing 40 black tea samples (brewed, instant, and sun tea) for polyphenols. This study assesses the reliability and relative validity of the ATQ and polyphenol database. Relative validity of estimates of black tea consumption was tested by comparing the ATQ with the traditional Arizona Food Frequency Questionnaire and four days of food records. The ATQ was tested for reproducibility of estimates of black (hot and iced) tea consumption and levels of black tea polyphenol intake. Correlations between two measures of intake taken 2 months apart ranged from 0.72 for black hot tea to 0.86 for black sun tea. Mean intakes (range) of total flavonoids for black tea consumers were 80.8 (3.0-588.0) mg/day at the first ATQ and 102.4 (4.5-802.3) mg/day at the second ATQ (r = 0.83, P < 0.001). The ATQ provided highly reproducible estimates of both total tea consumption and individual tea polyphenol intake. This instrument may be a useful tool in studies of the associations between tea consumption, tea polyphenols intake, and risk for chronic disease.

Fat intake and risk of squamous cell carcinoma of the skin

The varied effects of different classes of dietary fatty acids on carcinogenesis suggest that fatty acid composition is an important determining factor in tumor development. In the present study, we investigated the association between dietary n-3 and n-6 fatty acid intake and risk of squamous cell carcinoma of the skin (SCC). Data were taken from a population-based case-control study of skin SCC in Southeastern Arizona. Our data show a consistent tendency for a lower risk of SCC with higher intakes of n-3 fatty acids [p (for trend) = 0.055]. The adjusted odds ratios for increasing levels of n-3 fatty acids were 0.85 [95% confidence interval (CI) = 0.56-1.27] and 0.71 (95% CI = 0.49-1.00) compared with the lower level as the referent. For the ratio of n-3 to n-6 fatty acids, the odds ratios in successively higher levels were 0.88 (95% CI = 0.59-1.32) and 0.74 (95% CI = 0.51-1.05), suggesting a tendency toward decreased risk of SCC with increased intake of diets with high ratio of n-3 to n-6 fatty acid. More studies are clearly needed to elucidate the function of dietary fatty acids so that recommendations can be made to alter the human diet for cancer prevention, particularly in light of the increasing incidence of SCC of the skin.

Leptin--much more than a satiety signal

Much attention has focused on the effects of leptin as a central satiety agent. There is now a significant amount of evidence that leptin is active in the periphery. This review focuses on the ability of leptin to modify insulin sensitivity, tissue metabolism, stress responses, and reproductive function. Leptin's effect on several of these systems is mediated via the hypothalamic-pituitary axis. Therefore, although in vitro studies provide evidence for direct effects on specific tissues and metabolic pathways, it is essential to consider the interactions between leptin and other regulatory factors in vivo. Little is known about the regulation of peripheral receptor expression or the production of binding proteins. Both of these factors determine the bioactivity of circulating leptin and have the potential to induce a peripheral resistance to leptin, similar to the central "leptin resistance" observed in obese subjects. Future research will clarify which of the endocrine and metabolic actions of peripheral leptin are of physiological relevance and which should be considered a pharmacological manipulation.

Predictors for cutaneous basal- and squamous-cell carcinoma among actinically damaged adults

Risk factors for non-melanoma skin cancer among populations with evidence of precursor damage are not well described. We examined and compared risk factors associated with the development of cutaneous basal-cell (BCC) or squamous-cell (SCC) carcinoma among a group of 918 adults with significant sun damage (> or = 10 clinically assessable actinic keratoses) but no prior history of skin cancer. These adults were participants in a 5-year skin chemoprevention trial between 1985 and 1992, who had been randomized to the placebo group and followed for occurrence of skin cancer. During the study, a total of 129 first SCC and 164 first BCC lesions were diagnosed. The overall BCC and SCC incidence rates for this group of men and women, mean age 61 years, were 4,106 and 3,198 per 100,000 person-years, respectively. Different constitutional and exposure factors were independently associated with BCC compared to SCC. Only increased age independently predicted BCC occurrence among this population. In contrast, older age along with male gender, natural red hair color and adult residence in Arizona for 10 or more years independently predicted SCC occurrence. The substantial incidence of skin cancer found among this population confirms the need for active dermatological monitoring among individuals with multiple visible actinic lesions.