Erin C. McCanlies

Telomere Length, Current Perceived Stress, and Urinary Stress Hormones in Women

Telomeres are repetitive DNA sequences that cap and protect the ends of chromosomes; critically short telomeres may lead to cellular senescence or carcinogenic transformation. Previous findings suggest a link between psychosocial stress, shorter telomeres, and chronic disease risk. This cross-sectional study examined relative telomere length in relation to perceived stress and urinary stress hormones in a sample of participants (n = 647) in the National Institute of Environmental Health Sciences Sister Study, a cohort of women ages 35 to 74 years who have a sister with breast cancer. Average leukocyte telomere length was determined by quantitative PCR. Current stress was assessed using the Perceived Stress Scale and creatinine-adjusted neuroendocrine hormones in first morning urines. Linear regression models estimated differences in telomere length base pairs (bp) associated with stress measures adjusted for age, race, smoking, and obesity. Women with higher perceived stress had somewhat shorter telomeres [adjusted difference of −129bp for being at or above moderate stress levels; 95% confidence interval (CI), −292 to 33], but telomere length did not decrease monotonically with higher stress levels. Shorter telomeres were independently associated with increasing age (−27bp/year), obesity, and current smoking. Significant stress-related differences in telomere length were seen in women ages 55 years and older (−289bp; 95% CI, −519 to −59), those with recent major losses (−420bp; 95% CI, −814 to −27), and those with above-average urinary catecholamines (e.g., epinephrine: −484bp; 95% CI, −709 to −259). Although current perceived stress was only modestly associated with shorter telomeres in this broad sample of women, our findings suggest the effect of stress on telomere length may vary depending on neuroendocrine responsiveness, external stressors, and age. (Cancer Epidemiol Biomarkers Prev 2009;18(2):551–60)

Distribution of HER2V655 genotypes in breast cancer cases and controls in the United States

The minor variant frequency of a HER2 polymorphism (HER2(V655)) has been determined for 471 United States women enrolled in a multiracial case-control study. Allelic frequencies varied significantly by race. Genotypic distributions showed no excess breast cancer risk associated with inheritance of HER2(V655) either as carriers (OR=1.2, 95% CI=0.8-1.9), heterozygotes (OR=1.2, 95% CI=0.8-1.9), or homozygotes (OR=1.4, 95% CI=0.4-4.2). Nor was there a significant association when each racial group was considered separately. The current study suggests the HER2(V655) allele is not a breast cancer risk factor for Caucasians, African-Americans, or Latinas.

Parental Occupational Exposures and Autism Spectrum Disorder

Both self-report and industrial hygienist (IH) assessed parental occupational information were used in this pilot study in which 174 families (93 children with ASD and 81 unaffected children) enrolled in the Childhood Autism Risks from Genetics and Environment study participated. IH results indicated exposures to lacquer, varnish, and xylene occurred more often in the parents of children with ASD compared to the parents of unaffected children. Parents of children with ASD were more likely to report exposures to asphalt and solvents compared to parents of unaffected children. This study was limited by the small sample size, but results suggest that workplace exposures to some chemicals may be important in the etiology of ASD and deserve further investigation.

Employment and work schedule are related to telomere length in women.

Objectives To examine the association of employment and work schedule with shorter DNA telomeres, a marker of cellular ageing and disease risk factor, and consider whether differences were related to health, behaviours and sociodemographic factors, or varied by stress levels or menopausal status. Methods This cross-sectional analysis of 608 women aged 35–74 in the Sister Study examined determinants of relative telomere length (rTL) measured by quantitative PCR in leucocyte DNA. Age-adjusted regression models estimated base pair (bp) rTL differences for current and lifetime schedule characteristics (ie, part-time, full-time or overtime hours; multiple jobs; irregular hours; shiftwork; work at night). Covariates included race, smoking, perceived stress, sleep, physical activity, health and menopausal status, education, marital status, live births, children under 18, measured body mass index and urinary stress hormones. Results Compared with non-employed women with moderate or substantial past work histories (n=190), those currently working full-time (n=247; median 40 h/week) had a shorter rTL, an age-adjusted difference of −329 bp (95% CI −110 to −548). Longer-duration full-time work was also associated with shorter rTL (age-adjusted difference of −472 bp, 95% CI −786 to −158 for 20+ vs 1–5 years). Findings were not explained by health and demographic covariates. However, rTL differences for working at least full-time were greater in women with higher stress and epinephrine levels. Conclusions Current and long-term full-time work were associated with shorter rTL, with differences of similar magnitude to smoking and history of heart disease or diabetes. Longitudinal data with specific stress measures are needed to further evaluate the impact of work schedule on rTL.

C-reactive protein, interleukin-6, and posttraumatic stress disorder symptomology in urban police officers.

Our aim was to examine the relationship between the level of the inflammatory markers, C-reactive protein (CRP) and interleukin-6 (IL-6), and posttraumatic stress disorder (PTSD) symptomology in a random sample of 115 police officers. CRP was measured in citrated plasma using a particle enhanced immunonepholometric assay and IL-6 was measured in serum with a solid-phase quantitative sandwich ELISA. The presence of high PTSD symptomology was defined as having an Impact of Event Scale score (IES) of ≥ 26 compared to<26 (low PTSD symptomology). 28% of the officers had high PTSD symptomology. Mean levels of CRP and IL-6 did not differ significantly between officers with high PTSD symptomology and those with low symptomology (CRP: 0.76 mg/l vs. 0.97 mg/l; IL-6: 2.03 pg/ml vs. 1.74 pg/ml). We found no association of CRP and IL-6 levels with PTSD symptomology. This study was limited by sample size and its cross-sectional study design. A lack of association may occur if either CRP or IL-6 is elevated only at the onset of PTSD symptomology, or if inflammation is related to specific key components that define PTSD. Further research examining these relationships in a larger population may be worthwhile.

DNA sequence variants of p53: cancer and aging.

To the Editor: p53 has a critical role in cell-cycle control. As such, it has been identified as an important target in human carcinogenesis. However, since human p53 was cloned, ⩾10 DNA-sequence polymorphisms have been identified (Matlashewski et al. 1987; Weston and Godbold 1997). The codon 72 polymorphism (arginine/proline: G/C), the first to be described, has been the subject of ⩾31 epidemiological case-control studies that have explored a potential association with cancer (Olschwang et al. 1991; Weston et al. 1992, 1994, 1997; Zhang et al. 1992; Kawajiri et al. 1993; Birgander et al. 1995, 1996b; Jin et al. 1995; Sjalander et al. 1995a, 1996a; Wu et al. 1995; Murata et al. 1996; To-Figueras et al. 1996; Golovleva et al. 1997; Weston and Godbold 1997; Yung et al. 1997; Hayes et al. 1998; Helland et al. 1998; Hildesheim et al. 1998; Josefsson et al. 1998; Lanham et al. 1998; Minaguchi et al. 1998; Rosenthal et al. 1998; Storey et al. 1998; Tagawa et al. 1998; Wang-Gohrke et al. 1998). Although they err on the side of caution by citing Weston and Godbold (1997), Bonafe et al. (1999, p. 293), referring to the codon 72 polymorphism, state that “overall, the available data in the literature suggest that p53 variants may be considered as risk factors for some of the major neoplastic diseases in humans, such as lung, colorectal, breast and cervical cancer and are expected to affect survival.” With respect to codon 72, we contend that this is probably not the case. In the available data, lung cancer is the subject of eight studies (Weston et al. 1992, 1994; Kawajiri et al. 1993; Birgander et al. 1995; Jin et al. 1995; Murata et al. 1996; To-Figueras et al. 1996; Tagawa et al. 1998). Three studies claim a statistically significant association: in one study, a subset analysis suggested a relationship in lung cancer cases diagnosed at age <53 years (Jin et al. 1995); in the other two, the allelic frequencies were almost identical (and the difference was not significant) between cases and controls (Kawajiri et al. [1993] observed a proline-allele frequency of .35 for controls and .36 for cases [n = 347 and 328, respectively]). Murata et al. (1996) observed a proline-allele frequency of .40 for controls and .35 for cases (n = 152 and 191, respectively), but associations of cancer risk were claimed on the basis of higher numbers of homozygotes (Kawajiri et al. 1993; Murata et al. 1996). One study (Kawajiri et al. 1993) implicated proline; the other (Murata et al. 1996), arginine. Most recently, the relationship between cervical cancer, human papillomavirus (HPV) infection, and inheritance of the arginine allele has received considerable attention. The initial study, cited by Bonafe et al. (1999), showed a high degree of correlation between inheritance of the arginine allele and cervical cancer risk when HPV infection was present but not when it was absent (Storey et al. 1998). There are now eight studies of cervical cancer, but only one shows any association and seven are null (Hayes et al. 1998; Helland et al. 1998; Hildesheim et al. 1998; Josefsson et al. 1998; Lanham et al. 1998; Minaguchi et al. 1998; Rosenthal et al. 1998). There are five breast cancer studies (Kawajiri et al. 1993; Sjalander et al. 1996a; Weston et al. 1997; Helland et al. 1998; Wang-Gohrke et al. 1998); only one reached significance. Of the other published studies, a positive association has been claimed in 0/2 for nasopharyngeal cancer (Birgander et al. 1996b; Golovleva et al. 1997; Yung et al. 1997), 0/4 for colon cancer (Olschwang et al. 1991; Kawajiri et al. 1993; Jin et al. 1995; Sjalander et al. 1995a), 0/2 for bladder/urologic cancer (Kawajiri et al. 1993; Wu et al. 1995), 0/1 for acute myelogenous leukemia (Zhang et al. 1992), and 1/1 for stomach cancer (Kawajiri et al. 1993). Again, for stomach cancer, the allelic frequencies were not different for cases and controls, and an association of cancer risk with the arginine variant was claimed on the basis of higher numbers of arginine homozygotes in cases (Kawajiri et al. 1993; this report used the same control group noted above, and the proline-allele frequency in stomach cancer was .28 [n=140]). We contend, therefore, that the balance of the results of human molecular epidemiological association studies suggests that codon 72 allelism does not have an impact on human cancer risk. Specifically, at most, only 6 of 31 positive associations have been reported, and none have received consistent support in attempts to replicate them (Kawajiri et al. 1993; Jin et al. 1995; Murata et al. 1996; Sjalander et al. 1996a; Storey et al. 1998). Moreover, there is no obvious, plausible biological basis for an association of cancer risk with the codon 72 polymorphism. The impact of proline on the tertiary structure of a protein is disruption of α-helices. A proline residue resides at the monomeric position codon 71; therefore, at codon 72 there is no obvious consequence to proline. Results were reported for p53, codon 72, genotype frequencies in healthy Italian centenarians and younger controls (Bonafe et al. 1999). The expectation was of allelic winnowing in the case of a codon 72 variant associated with cancer susceptibility and subsequent survival. The frequency of proline-allele carriers was .539 in controls and .506 in centenarians, 3.3% lower (and the corresponding allelic frequency was 2.7% lower, but the difference was not significant). We conjecture that their comparison of centenarians (n=176) with younger controls (n=204) is too crude to detect the predicted allelic winnowing (Bonafe et al. 1999). First, the cause of death from cancer in the Italian population is ∼23% (WHO 1987; Lopez 1990). Second, even though we do not agree that there is good evidence for an association between inheritance at codon 72 and cancer susceptibility, because of the molecular epidemiological data reviewed above, let us assume that the proline variant carries a relative risk of 1.5–2.0 (Kawajiri et al. 1993). On the basis of this assumption we might expect a reduction of 3.0%–4.8% in proline-allele carriers as the population ages (table 1 shows a simulated 2×2 table for a standard population of 1,000 persons, given a relative risk of 1.5 and a cancer death rate of 23% [WHO 1987; Lopez 1990]). In the letter by Bonafe et al. (1999), a reduction of 3.3% in the frequency of proline-allele carriers among centenarians was reported. This reduction is consistent with their hypothesis, although the authors suggest that it is not (Bonafe et al. 1999). Moreover, our corresponding projected reduction in allelic frequency is 2.8% for a relative risk of 1.5; Bonafe et al. (1999) observed a 2.7% reduction in frequency. However, to have, at a significance level of .05, 80% power to detect a 3.0%–4.8% reduction in the prevalence of proline-allele carriers, a minimum of 2,002–3,178 people would be needed, given a relative risk of 2.0; and 5,176–8,182 would be needed, given a relative risk of 1.5 (results of power calculations are given in table 2). Table 1 Simulated Relative-Risk Calculation for a Standard Population of 1,000 Persons[Note] Table 2 Power Calculations Notwithstanding these conclusions and observations, we believe that p53 allelism is an important cancer-susceptibility factor but that it is more complex than that simply defined by the polymorphism at codon 72. A series of studies by a Swedish group (Beckman et al. 1994; Birgander et al. 1995, 1996a, 1996b; Sjalander et al. 1995a, 1995b, 1996a, 1996b) indicated that a constellation of three p53 polymorphisms (intron 3, codon 72, and intron 6) constituted a haplotype predictive of increased breast cancer risk (odds ratio [OR] = 2.9, 95% confidence interval [CI] = 1.4–6.3 [Sjalander et al. 1996a]). Haplotypes were deduced on the basis of population frequencies of the individual polymorphisms. First, estimates of pairwise haplotype frequencies were calculated, and extended haplotype frequencies were deduced from this information. A subsequent study examined the same question but used a PCR-based method for physical determination of the haplotypes (Weston et al. 1997, 1998). The results of the latter study were consistent with those reported in the study by Sjalander et al. (1996a) (OR = 2.5, 95% CI = 1.3–4.8, in postmenopausal women) and further implicated a specific haplotype, designated “p531-2-1.” More recently, a third study, estimating extended haplotypes of these three polymorphisms in a German population, provided results consistent with an elevated breast cancer risk associated with inheritance of p531-2-1 (OR = 2.0, 95% CI = 1.0–3.9 [Wang-Gohrke et al. 1998]). It is to be noted that this latest report has adopted an allelic nomenclature different from that developed by Beckman et al. (1994) and adopted by others (Sjalander et al. 1996a; Weston et al. 1997, 1998). The balance of the results of human breast cancer studies of molecular epidemiological haplotype association—specifically, three positive associations in three studies—suggests that inheritance of the p531-2-1 haplotype does have an impact on human breast cancer risk (Sjalander et al. 1996a; Wang-Gohrke et al. 1998; Weston et al. 1998). However, more research is needed to resolve this question. In our laboratory, we have adopted a complementary molecular epidemiological and basic-science approach. First, we are trying again to replicate the epidemiological studies of breast cancer, by using the PCR-based physical haplotype method in a population-based case-control study that has sufficient power. Second, we have derived normal human mammary cell strains with known haplotypes and plan to test their response to suspect breast carcinogens.

Impact of negatively charged patches on the surface of MHC class II antigen-presenting proteins on risk of chronic beryllium disease

Chronic beryllium disease (CBD) is a granulomatous lung disease that occurs primarily in workers who are exposed to beryllium dust or fumes. Although exposure to beryllium is a necessary factor in the pathobiology of CBD, alleles that code for a glutamic acid residue at the 69th position of the HLA-DPβ1 gene have previously been found to be associated with CBD. To date, 43 HLA-DPβ1 alleles that code for glutamic acid 69 (E69) have been described. Whether all of these E69 coding alleles convey equal risk of CBD is unknown. The present study demonstrates that, on the one hand, E69 alleloforms of major histocompatibility complex class II antigen-presenting proteins with the greatest negative surface charge convey the highest risk of CBD, and on the other hand, irrespective of allele, they convey equal risk of beryllium sensitization (BeS). In addition, the data suggest that the same alleles that cause the greatest risk of CBD are also important for the progression from BeS to CBD. Alleles convey the highest risk code for E26 in a constant region and for E69, aspartic acid 55 (D55), E56, D84 and E85 in hypervariable regions of the HLA-DPβ1 chain. Together with the calculated high binding affinities for beryllium, these results suggest that an adverse immune response, leading to CBD, is triggered by chemically specific metal–protein interactions.

Positive psychological factors are associated with lower PTSD symptoms among police officers: post Hurricane Katrina.

Following Hurricane Katrina, police officers in the New Orleans geographic area faced a number of challenges. This cross-sectional study examined the association between resilience, satisfaction with life, gratitude, posttraumatic growth, and symptoms of posttraumatic stress disorder in 84 male and 30 female police officers from Louisiana. Protective factors were measured using the Connor-Davidson Resilience scale, Satisfaction with Life Scale, the Gratitude Questionnaire, and the Posttraumatic Growth inventory. Symptoms of posttraumatic stress disorder were measured using the Posttraumatic Stress Disorder Checklist--Civilian (PCL-C). Potential associations were measured using linear regression and analysis of variance. Models were adjusted for age, sex, race, education, and alcohol. Mean PCL-C symptoms were 29.5 ± 14.5 for females and 27.8 ± 12.1 for males. Adjusted mean levels of PCL-C symptoms significantly decreased as quartiles of resilience (p < .001), satisfaction with life (p < .001), and gratitude (p < .001) increased. In contrast, PCL-C symptoms were not associated with posttraumatic growth in this sample. These results indicate that positive factors such as resilience, satisfaction with life, and gratitude may help mitigate symptoms of posttraumatic stress disorder. To further explore these relationships, longitudinal follow-up in a larger population would be of interest.

Metabolic syndrome and sleep duration in police officers.

OBJECTIVES To examine associations for sleep quality and quantity with metabolic syndrome (MS) and its five components in police officers. PATIENTS OR PARTICIPANTS The study population consisted of 98 randomly selected officers (39 women and 59 men) for whom MS and sleep data were available. METHODS Sleep duration (categorized as short < 6 hours, long ≥ 6 hours) for the past week and quality of sleep were collected by interviewer-administered questionnaires. MS was assessed using standard criteria. Generalized linear models were used to assess associations between sleep duration or sleep quality and MS, and the mean number of MS components. RESULTS Metabolic syndrome was present in 22.0% and 2.6% of the male and female officers, respectively. Women with short sleep had a significantly higher mean number of MS components (mean=1.43) than those with longer sleep (mean=0.81, p=0.0316). Officers who stopped breathing during the night had more MS components (mean=2.43) compared to those who did not (mean =1.13, p=0.0206). CONCLUSIONS Sleep duration and quality were associated with the mean number of MS components, particularly in women. Future research should examine these associations prospectively, in a larger cohort, exploring possible gender differences.

Chronic Beryllium Disease, HLA-DPB1, and the DP Peptide Binding Groove

Multiple epidemiologic studies demonstrate associations between chronic beryllium disease (CBD), beryllium sensitization (BeS), and HLA-DPB1 alleles with a glutamic acid residue at position 69 (E69). Results suggest that the less-frequent E69 variants (non-*0201/*0202 alleles) might be associated with greater risk of CBD. In this study, we sought to define specific E69-carrying alleles and their amino acid sequences in the DP peptide binding groove, as well as their relationship to CBD and BeS risk, using the largest case control study to date. We enrolled 502 BeS/CBD subjects and 653 beryllium-exposed controls from three beryllium industries who gave informed consent for participation. Non-Hispanic white cases and controls were frequency-matched by industry. HLA-DPB1 genotypes were determined using sequence-specific primer PCR. The E69 alleles were tested for association with disease individually and grouped by amino acid structure using logistic regression. The results show that CBD cases were more likely than controls to carry a non-*02 E69 allele than an *02 E69, with odds ratios (95% confidence interval) ranging from 3.1 (2.1–4.5) to 3.9 (2.6–5.9) (p < 0.0001). Polymorphic amino acids at positions 84 and 11 were associated with CBD: DD versus GG, 2.8 (1.8–4.6), p < 0.0001; GD versus GG, 2.1 (1.5–2.8), p < 0.0001; LL versus GG, 3.2 (1.8–5.6), p < 0.0001; GL versus GG, 2.8 (2.1–3.8), p < 0.0001. Similar results were found within the BeS group and CBD/BeS combined group. We conclude that the less frequent E69 alleles confer more risk for CBD than does *0201. Recent studies examining how the composition and structure of the binding pockets influence peptide binding in MHC genes, as well of studies showing the topology of the TCR to likely bind DPB1 preferentially, give plausible biological rationale for these findings.