Comparing structural credit models and their applicability to banks

Throughout this thesis we have presented a narrow overview of the research field of structural credit models and their applicability to banks. We have focused on two of the newer contributions to the field by Nagel and Purnanandam (2019)(NP) and Atreya, Mjøs and Persson (2019)(AMP), and provided a thorough, but not exhaustive, comparison and evaluation of these models. We have found that the different approaches of the two models provide logical results for both risk-neutral probability of default (RNPD)1 and credit spreads2, each displaying strengths and weaknesses compared to the banking industry. Both models account for the crucial characteristic of banks in that the value of their loans, and therefore their assets, have a naturally capped upside. Accordingly, both models rely on the use of a standard Brownian motion to describe the uncertainty of borrower asset values, and then value the banks claim on these through their respective loans. In our comparison we find that the NP model provides somewhat higher estimates for both RNPD and credit spread relative to the AMP model for different borrower risk parameters. We then discuss various characteristics and assumptions of both models as explanatory for the observed deviation between the models. We also discuss whether each of these characteristics appear realistic in light of the banking industry. Lastly, we touch upon additional common deviations from the banking industry of structural credit models like the ones we compare. Here we point to the complexity of loan types, debt structure, bank income sources and bank’s borrowers as difficult elements to incorporate in detail. Nonetheless, we argue that the models in focus presents reasonable simplifications of the complex banking industry.nhhma

Adult Height, Insulin Levels and 17β-Estradiol in Young Women

Background: Adult height and insulin levels have independently been associated with breast cancer risk. However, little is known about whether these factors influence estradiol levels. Thus, we hypothesize that adult height in combination with insulin levels may influence premenopausal 17β-estradiol throughout the entire menstrual cycle of possible importance of breast cancer risk. Methods: Among 204 healthy women, aged 25-35 years who participated in the Norwegian EBBA I study, birth weight and age at menarche were assessed by questionnaire, personal health record and interview. 17β-estradiol concentrations were estimated by daily saliva samples throughout one entire menstrual cycle using radioimmunoassay (RIA). Measures of height (cm) were taken as well as waist circumference (cm), body mass index (BMI kg/m2) and total fat percentage (DEXA % fat). Fasting blood samples were drawn, and serum concentrations of insulin were determined. Results: The women reported a mean height of 166.5 cm, birth weight of 3389 g and age at menarche 13.1 years. Mean BMI was 24.4 kg/m2, mean waist circumference 79.5 cm and mean total fat percentage 34.1%. Women with an adult height of more than 170 cm and insulin levels higher than 90 pmol/L experienced on average an 37.2 % increase in 17β- estradiol during an entire menstrual cycle compared to those with the same height, and insulin levels below 90 pmol/L. Moreover, this was also observed throughout the entire menstrual cycle. Conclusion: Our findings support that premenopausal levels of 17β-estradiol vary in response to adult height and insulin levels, suggesting that women who become taller are put at risk for higher estradiol levels when their insulin levels rise of possible importance for breast cancer risk.Anthropolog

Ovarian hormones and reproductive risk factors for breast cancer in premenopausal women: the Norwegian EBBA-I study

BACKGROUND: Ovarian hormones, parity and length of 'menarche-to-first birth' time interval are known risk factors for breast cancer, yet the associations between I 7$\beta$-estradiol, progesterone and these reproductive factors remain unclear. METHODS: A total of 204 women (25-35 years) who participated in the Norwegian EBBA-I study collected daily saliva samples for one complete menstrual cycle, and filled in a reproductive history questionnaire. Anthropometry was measured and saliva samples were analyzed for ovarian hormones. Associations between parity, the interval and ovarian hormones, and effects of hormone-related lifestyle factors were studied in linear regression models. RESULTS: Mean age was 30.7 years, and age of menarche 13.1 years. Parous women had on average 1.9 births, and age at first birth was 24.5 years. No association was observed between parity and ovarian steroids. In nulliparous women, higher waist circumference ($\ge$)77.75 cm) and longer oral contraceptive (OC) use ($\ge$)3 years) were associated with higher levels of I 7$\beta$-estradiol. Short (13.5 years) 'menarche-to-first birth' interval was associated with higher overall mean (P$_{trend}$ = 0.029), 47% higher maximum peak and 30% higher mid-cycle levels of I 7$\beta$-estradiol. We observed a 2.6% decrease in overall mean salivary I 7$\beta$-estradiol with each 1-year increase in the interval. CONCLUSIONS: Nulliparous women may be more susceptible to lifestyle factors, abdominal overweight and past OC use, influencing metabolic and hormonal profiles and thus breast cancer risk. Short time between 'menarche-to-first birth' is linked to higher ovarian hormone levels among regularly cycling women, suggesting that timing of first birth is related to fecundity.Human Evolutionary Biolog

State injury profile for Georgia

Estrogen and progesterone are key factors in the development of breast cancer, but it remains unclear whether these hormones are associated with mammographic density phenotypes in premenopausal women. We measured percent mammographic density, nondense area, and absolute mammographic density using computer-assisted breast density readings (Madena) from digitized mammograms taken on a scheduled day of the menstrual cycle (day 7–12) among 202 healthy, premenopausal women (Energy Balance and Breast cancer Aspects Study-I). Daily salivary concentrations of 17β-estradiol and progesterone throughout an entire menstrual cycle and fasting morning serum concentrations of hormones on 3 specific days of the menstrual cycle were assessed. Salivary and serum 17β-estradiol and progesterone were positively associated with percent mammographic density, we observed by 1 SD increase in overall salivary estradiol (β-value equal to 2.07, P=0.044), luteal salivary progesterone (β-value equal to 2.40, P=0.020). Women with above-median percent mammographic density had a 20% higher mean salivary 17β-estradiol level throughout the menstrual cycle. The odds ratio for having above-median percent mammographic density (>28.5%) per 1 SD increase in overall salivary 17β-estradiol was 1.66 (95% confidence interval 1.13–2.45). Women in the top tertile of the overall average daily 17β-estradiol concentrations had an odds ratio of 2.54 (confidence interval 1.05–6.16) of above-median percent mammographic density compared with women in the bottom tertile. Our finding of a relationship between estrogen, progesterone, and percent mammographic density and not with other mammographic density phenotypes in premenopausal women is biologically plausible, but needs to be replicated in larger studies

Comparing structural credit models and their applicability to banks

Throughout this thesis we have presented a narrow overview of the research field of structural credit models and their applicability to banks. We have focused on two of the newer contributions to the field by Nagel and Purnanandam (2019)(NP) and Atreya, Mjøs and Persson (2019)(AMP), and provided a thorough, but not exhaustive, comparison and evaluation of these models. We have found that the different approaches of the two models provide logical results for both risk-neutral probability of default (RNPD)1 and credit spreads2, each displaying strengths and weaknesses compared to the banking industry. Both models account for the crucial characteristic of banks in that the value of their loans, and therefore their assets, have a naturally capped upside. Accordingly, both models rely on the use of a standard Brownian motion to describe the uncertainty of borrower asset values, and then value the banks claim on these through their respective loans. In our comparison we find that the NP model provides somewhat higher estimates for both RNPD and credit spread relative to the AMP model for different borrower risk parameters. We then discuss various characteristics and assumptions of both models as explanatory for the observed deviation between the models. We also discuss whether each of these characteristics appear realistic in light of the banking industry. Lastly, we touch upon additional common deviations from the banking industry of structural credit models like the ones we compare. Here we point to the complexity of loan types, debt structure, bank income sources and bank’s borrowers as difficult elements to incorporate in detail. Nonetheless, we argue that the models in focus presents reasonable simplifications of the complex banking industry

Lipoprotein subfractions by nuclear magnetic resonance are associated with tumor characteristics in breast cancer

Background: High-Density Lipoprotein (HDL)-cholesterol, has been associated with breast cancer development, but the association is under debate, and whether lipoprotein subfractions is associated with breast tumor characteristics remains unclear. Methods: Among 56 women with newly diagnosed invasive breast cancer stage I/II, aged 35–75 years, pre-surgery overnight fasting serum concentrations of lipids were assessed, and body mass index (BMI) was measured. All breast tumors were immunohistochemically examined in the surgical specimen. Serum metabolomics of lipoprotein subfractions and their contents of cholesterol, free cholesterol, phospholipids, apolipoprotein-A1 and apolipoprotein-A2, were assessed using nuclear magnetic resonance. Principal component analysis, partial least square analysis, and uni- and multivariable linear regression models were used to study whether lipoprotein subfractions were associated with breast cancer tumor characteristics. Results: The breast cancer patients had following means: age at diagnosis: 55.1 years; BMI: 25.1 kg/m2; total-Cholesterol: 5.74 mmol/L; HDL-Cholesterol: 1.78 mmol/L; Low-Density Lipoprotein (LDL)-Cholesterol: 3.45 mmol/L; triglycerides: 1.18 mmol/L. The mean tumor size was 16.4 mm, and the mean Ki67 hotspot index was 26.5 %. Most (93 %) of the patients had estrogen receptor (ER) positive tumors (≥1 % ER+), and 82 % had progesterone receptor (PgR) positive tumors (≥10 % PgR+). Several HDL subfraction contents were strongly associated with PgR expression: Apolipoprotein-A1 (β 0.46, CI 0.22–0.69, p < 0.001), HDL cholesterol (β 0.95, CI 0.51–1.39, p < 0.001), HDL free cholesterol (β 2.88, CI 1.28–4.48, p = 0.001), HDL phospholipids (β 0.70, CI 0.36–1.04, p < 0.001). Similar results were observed for the subfractions of HDL1-3. We observed inverse associations between HDL phospholipids and Ki67 (β -0.25, p = 0.008), and in particular between HDL1’s contents of cholesterol, phospholipids, apolipoprotein-A1, apolipoprotein-A2 and Ki67. No association was observed between lipoproteins and ER expression. Conclusion: Our findings hypothesize associations between different lipoprotein subfractions, and PgR expression, and Ki 67 % in breast tumors. These findings may have clinical implications, but require confirmation in larger studies

Lipoprotein subfractions by nuclear magnetic resonance are associated with tumor characteristics in breast cancer

Background: High-Density Lipoprotein (HDL)-cholesterol, has been associated with breast cancer development, but the association is under debate, and whether lipoprotein subfractions is associated with breast tumor characteristics remains unclear. Methods: Among 56 women with newly diagnosed invasive breast cancer stage I/II, aged 35–75 years, pre-surgery overnight fasting serum concentrations of lipids were assessed, and body mass index (BMI) was measured. All breast tumors were immunohistochemically examined in the surgical specimen. Serum metabolomics of lipoprotein subfractions and their contents of cholesterol, free cholesterol, phospholipids, apolipoprotein-A1 and apolipoprotein-A2, were assessed using nuclear magnetic resonance. Principal component analysis, partial least square analysis, and uni- and multivariable linear regression models were used to study whether lipoprotein subfractions were associated with breast cancer tumor characteristics. Results: The breast cancer patients had following means: age at diagnosis: 55.1 years; BMI: 25.1 kg/m2 ; total-Cholesterol: 5.74 mmol/L; HDL-Cholesterol: 1.78 mmol/L; Low-Density Lipoprotein (LDL)-Cholesterol: 3.45 mmol/L; triglycerides: 1.18 mmol/L. The mean tumor size was 16.4 mm, and the mean Ki67 hotspot index was 26.5 %. Most (93 %) of the patients had estrogen receptor (ER) positive tumors (≥1 % ER+), and 82 % had progesterone receptor (PgR) positive tumors (≥10 % PgR+). Several HDL subfraction contents were strongly associated with PgR expression: Apolipoprotein-A1 (β 0.46, CI 0.22–0.69, p < 0.001), HDL cholesterol (β 0.95, CI 0.51–1.39, p < 0.001), HDL free cholesterol (β 2.88, CI 1.28–4.48, p = 0.001), HDL phospholipids (β 0.70, CI 0.36–1.04, p < 0.001). Similar results were observed for the subfractions of HDL1-3. We observed inverse associations between HDL phospholipids and Ki67 (β -0.25, p = 0.008), and in particular between HDL1’s contents of cholesterol, phospholipids, apolipoprotein-A1, apolipoprotein-A2 and Ki67. No association was observed between lipoproteins and ER expression. Conclusion: Our findings hypothesize associations between different lipoprotein subfractions, and PgR expression, and Ki 67 % in breast tumors. These findings may have clinical implications, but require confirmation in larger studie

Influence of birth weight and adult body composition on 17β\beta-estradiol levels in young women

Higher exposure to light at night per se and through decrease in sleep duration and night shift work may suppress serum melatonin levels, which in turn may increase the reproductive hormone levels. High levels of steroid hormones, especially estrogens, may be associated with an increase of the breast cancer risk. This study investigated whether variation in the sleep duration during one entire menstrual cycle corresponds to variation in estradiol levels in healthy, urban women of reproductive age. Ninthy five regularly menstruating women ages 24-36 collected daily saliva samples for one entire menstrual cycle and recorded the number of hours of sleep per night (sleep duration). Saliva samples were analyzed for concentration of 17-ß estradiol (E2). We documented, after adjustments for sleep duration, a positive relationship between the sleep variation (coefficient of variation in sleep duration - sleep CV) and estradiol levels in women of reproductive age. Mean levels of E2 differed significantly in women from the lowest sleep CV quartile in comparison to other quartiles (p<0.001). The low sleep variation group, that is the women who sleep regularly, had mean E2 levels 60% lower than other groups. These results suggest that sleep variation significantly correlates with E2 levels, while sleep duration does not show a statistically significant relationship. According to the breast cancer development hypothesis, increasing the lifetime exposure to endogenous estrogens could result in higher risk of breast cancer.AnthropologyHuman Evolutionary Biolog