Polygenic risk score as a determinant of risk of keratinocyte cancer in an Australian population-based cohort

BACKGROUND

Keratinocyte cancer (KC) risk is determined by genetic and environmental factors. Genetic risk can be quantified by polygenic risk scores (PRS), which sum the combined effects of single nucleotide polymorphisms (SNPs).

OBJECTIVES

Our objective here was to evaluate the contribution of the summed genetic score to predict the KC risk in the phenotypically well-characterised Nambour population.

METHODS

We used PLINK v1.90 to calculate PRS for 432 cases, 566 controls, using 78 genome-wide independent SNPs that are associated with KC risk. We assessed the association between PRS and KC using logistic regression, stratifying the cohort into 3 risk groups (high 20%, intermediate 60%, low 20%).

RESULTS

The fully adjusted model including traditional risk factors (phenotypic and sun exposure-related), showed a significant 50% increase in odds of KC per standard deviation of PRS (odds ratio (OR) =1.51; 95% confidence interval (CI) =1.30-1.76, P=5.75 × 10^-8 ). Those in the top 20% PRS had over three times the risk of KC of those in the lowest 20% (OR=3.45; 95% CI=2.18-5.50, P=1.5×10^-7 ) and higher absolute risk of KC per 100 person-years of 2.96 compared with 1.34. Area under the ROC curve increased from 0.72 to 0.74 on adding PRS to the fully adjusted model.

CONCLUSIONS

These results show that PRS can enhance the prediction of KC above traditional risk factors.

Diet quality is associated with primary melanoma thickness

Background

Objective

Methods

Results

Conclusions

Statins may reduce disease recurrence in patients with ulcerated primary melanoma

BACKGROUND

Statins may restrict the cellular functions required for melanoma growth and metastasis.

OBJECTIVES

To determine whether long-term statin use commenced before diagnosis of a primary melanoma is associated with reduced risk of melanoma recurrence.

METHODS

We prospectively followed a cohort of patients newly diagnosed between 2010 and 2014 with localized tumour-stage T1b to T4b melanoma in Queensland, Australia. We used Cox regression analyses to examine associations between long-term statin use and melanoma recurrence for the entire cohort, and then separately by sex and by presence of ulceration, due to evidence of effect modification.

RESULTS

Among 700 patients diagnosed with stage T1b to T4b primary melanoma (mean age 62 years, 59% male, 28% with ulcerated tumours), 94 patients (13%) developed melanoma recurrence within 2 years. Long-term statin users (n = 204, 29%) had a significantly lower risk of disease recurrence than nonusers [adjusted hazard ratio (HR_adj ) 0·55, 95% confidence Interval (CI) 0·32-0·97] regardless of statin subtype or potency. Compared with nonusers of statins, risk of recurrence was significantly decreased in male statin users (HR_adj 0·39, 95% CI 0·19-0·79) but not in female statin users (HR_adj 0·82, 95% CI 0·29-2·27) and in statin users with ulcerated (HR_adj 0·17, 95% CI 0·05-0·52) but not nonulcerated (HR_adj 0·91, 95% CI 0·46-1·81) primary melanoma.

CONCLUSIONS

Statins commenced before melanoma diagnosis may reduce the risk of melanoma recurrence, especially in men and in those with ulcerated tumours. Clinical trial evaluation of the potential role of statins in improving the prognosis of high-risk melanoma is warranted.

A prospective study of cigarette smoking and basal cell carcinoma

To investigate the relationship between smoking and primary basal cell carcinoma (BCC), we analyzed data from a 16 year prospective study among randomly selected adults in Nambour, Queensland, Australia. Participants underwent a skin examination in 1992 and took part in an intervention study and follow-up. Information about complexion type and smoking habits including duration and number of cigarettes smoked per day and sun exposure behavior were collected at baseline in 1992, with updates to end of follow-up in 2007. Newly-diagnosed BCCs were ascertained from regional pathology laboratories. Relative risks (RR) of BCC among former and current smokers were estimated using generalized linear models specifying a Poisson distribution with robust error variance and (log) person-years at-risk as offset, adjusting for BCC risk factors. From 1992 to 2007, 281 BCCs were diagnosed in 1,277 participants with available smoking history and no past BCC. Relative to non-smokers, a non-significant inverse association between current smoking and BCC was seen (RR 0.69; 95 % CI 0.45-1.05) but not for former smokers (RR 1.05; 95 % CI 0.84-1.31). Amongst current smokers, inverse associations with BCC were found in those who smoked for up to 18 years (RR 0.44) but not more and those who smoked up to 15 cigarettes per day but not more. The associations with both current and former smoking varied by degree of sunburn propensity. The modest inverse association between current smoking and BCC is considered unlikely to be causal given lack of clear relation with duration or intensity of smoking.

Dairy consumption and patterns of mortality of Australian adults

BACKGROUND/OBJECTIVES

Dairy foods contain various nutrients that may affect health. We investigated whether intake of dairy products or related nutrients is associated with mortality due to cardiovascular disease (CVD), cancer and all causes.

SUBJECTS/METHODS

We carried out a 16-year prospective study among a community-based sample of 1529 adult Australians aged 25-78 years at baseline. Habitual intakes of dairy products (total, high/low-fat dairy, milk, yoghurt and full-fat cheese), calcium and vitamin D were estimated as mean reported intake using validated food frequency questionnaires (FFQs) self-administered in 1992, 1994 and 1996. National Death Index data were used to ascertain mortality and cause of death between 1992 and 2007. Hazard ratios (HRs) were calculated using Cox regression analysis.

RESULTS

During an average follow-up time of 14.4 years, 177 participants died, including 61 deaths due to CVD and 58 deaths due to cancer. There was no consistent and significant association between total dairy intake and total or cause-specific mortality. However, compared with those with the lowest intake of full-fat dairy, participants with the highest intake (median intake 339 g/day) had reduced death due to CVD (HR: 0.31; 95% confidence interval (CI): 0.12-0.79; P for trend=0.04) after adjustment for calcium intake and other confounders. Intakes of low-fat dairy, specific dairy foods, calcium and vitamin D showed no consistent associations.

CONCLUSIONS

Overall intake of dairy products was not associated with mortality. A possible beneficial association between intake of full-fat dairy and cardiovascular mortality needs further assessment and confirmation.