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Initially submitted February 1, 2016; accepted for publication August 4, 2016. The ability to classify people according to their underlying genetic susceptibility to a disease is increasing with new knowledge, better family data, and more sophisticated risk prediction models, allowing for more effective prevention and screening. To do so, however, we need to know whether risk associations are the same for people with different genetic susceptibilities. To illustrate one way to estimate such gene-environment interactions, we used prospective data from 3 Australian family cancer cohort studies, 2 enriched for familial risk of breast cancer. There were 288 incident breast cancers in 9,126 participants from 3,222 families. We used Cox proportional hazards models to investigate whether associations of breast cancer with body mass index (BMI; weight (kg)/height (m)2) at age 18-21 years, BMI at baseline, and change in BMI differed according to genetic risk based on lifetime breast cancer risk from birth, as estimated by BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) software, adjusted for age at baseline data collection. Although no interactions were statistically significant, we have demonstrated the power with which gene-environment interactions can be investigated using a cohort enriched for persons with increased genetic risk and a continuous measure of genetic risk based on family history. [ABSTRACT FROM AUTHOR]

Background: Reported associations between protein intake from different sources and type 2 diabetes (T2D) have been inconsistent. Objective: We prospectively examined the relations of total, animal, and plant protein intakes with incident T2D. Design: We followed 21,523 participants (women: 61.7%) between 1990 and 2007 from the Melbourne Collaborative Cohort Study who were free of diabetes, cardiovascular disease, cancer, and kidney stones at baseline. We also conducted a meta-analysis that included the results from our cohort and from 10 previous prospective studies. Results: A total of 929 new cases (4.3%) of T2D were documented during a mean of 11.7 y of follow-up. Multivariate-adjusted ORs for incident T2D in the highest compared with lowest quintiles of total and animal protein intakes as percentages of energy were 1.23 (95% CI: 0.96, 1.56; P-trend = 0.029) and 1.29 (95% CI: 0.99, 1.67; P-trend = 0.014), respectively. These associations appeared to be greater in men and in participants with normal baseline plasma glucose, body mass index, or blood pressure. Plant protein intake was inversely associated with incident T2D in women only (OR; 0.60; 95% CI: 0.37, 0.99). In the meta-analysis of 11 prospective cohort studies with 505,624 participants and 37,918 T2D cases (follow-up range: 5-24 y), pooled RRs for the comparison of the highest with lowest categories of total, animal, and plant protein intakes were 1.09 (95% CI: 1.06, 1.13), 1.19 (95% CI: 1.11, 1.28), and 0.95 (95% CI: 0.89, 1.02), respectively. Associations between animal protein intake and T2D were similar across sex, geographic region, length of follow-up, study quality, and method of expressing protein intake. An inverse association between plant protein intake and T2D was observed in women (RR: 0.93; 95% CI: 0.85, 1.00) and in US populations (RR: 0.91; 95% CI: 0.84, 0.97). Conclusion: Higher intakes of total and animal protein were both associated with increased risks of T2D, whereas higher plant protein intake tended to be associated with lower risk of T2D. [ABSTRACT FROM AUTHOR]

Background Conventionally, cohort studies have assessed the association between alcohol and all-cause mortality by using alcohol intake at enrolment. Methods In the Melbourne Collaborative Cohort Study, participants were asked about usual frequency and quantity of beverage-specific alcohol intake for 10-year periods starting at age 20 from which current, past and lifetime intakes were calculated. We used Cox regression to estimate hazard ratios for mortality for 39 577 participants of the Melbourne Collaborative Cohort Study aged 40-69 at baseline. Results After a mean follow-up of 15 years/person, we identified 4639 deaths. Associations between all-cause mortality and lifetime, current (baseline) and past intake were J shaped, with lower mortality at low intake (e.g. <40 g/dayfor men and 10 g/day for women using lifetime intake) and elevated mortality at higher intake. For men, consistent light-to-moderate drinking (>0-39/>0-39 g/day) from age 20 to baseline age was associated with a 16% lower mortality, while heavy drinking at both ages (≥80/≥40 and ≥40/0 g/day) was associated with higher mortality compared with stable abstinence. Conclusions Our findings support a reduced mortality risk associated with low-dose drinking but also highlight a higher mortality risk for consistent heavy drinking from a young age. [ABSTRACT FROM AUTHOR]

Background: Individual studies have suggested that circulating carot-enoids, retinol, or tocopherols may be associated with prostate cancer risk, but the studies have not been large enough to provide precise estimates of associations, particularly by stage and grade of disease. Objective: The objective of this study was to conduct a pooled analysis of the associations of the concentrations of 7 carotenoids, retinol, α-tocopherol, and γ-tocopherol with risk of prostate cancer and to describe whether any associations differ by stage or grade of the disease or other factors. Design: Principal investigators of prospective studies provided individual participant data for prostate cancer cases and controls. Risk by study-specific fifths of each biomarker was estimated by using multivariable-adjusted conditional logistic regression in matched case-control sets. Results: Data were available for up to 11,239 cases (including 1654 advanced stage and 1741 aggressive) and 18,541 controls from 15 studies. Lycopene was not associated with overall risk of prostate cancer, but there was statistically significant heterogeneity by stage of disease, and the OR for aggressive disease for the highest compared with the lowest fifth of lycopene was 0.65 (95% CI: 0.46, 0.91; P-trend = 0.032). No other carotenoid was significantly associated with overall risk of prostate cancer or with risk of advanced-stage or aggressive disease. For retinol, the OR for the highest compared with the lowest fifth was 1.13 (95% CI: 1.04, 1.22; P-trend = 0.015). For α-tocopherol, the OR for the highest compared with the lowest fifth was 0.86 (95% CI: 0.78, 0.94; P-trend < 0.001), with significant heterogeneity by stage of disease; the OR for aggressive prostate cancer was 0.74 (95% CI: 0.59, 0.92; P-trend = 0.001). γ-Tocopherol was not associated with risk. Conclusions: Overall prostate cancer risk was positively associated with retinol and inversely associated with α-tocopherol, and risk of aggressive prostate cancer was inversely associated with lycopene and α-tocopherol. Whether these associations reflect causal relations is unclear. [ABSTRACT FROM AUTHOR]

Objective There is evidence of a vascular contribution to the pathogenesis of osteoarthritis (OA). The aim of this study was to examine the association between popliteal artery wall thickness, which was previously shown to be associated with the risk of OA, and structural changes in the knee in an asymptomatic cohort. Methods A total of 297 adults with no significant knee pain, injury, or history of clinical knee disease were recruited. Participants underwent magnetic resonance imaging of the knee at baseline and 2 years later. Popliteal artery wall thickness, knee cartilage volume, and bone marrow lesions (BMLs) were assessed. Results Of 278 participants with valid popliteal artery wall thickness measurements, 254 (91.4%) completed the 2-year followup assessment. After adjusting for age, sex, body mass index, and tibial bone area, increased popliteal artery wall thickness was found to be associated with a reduced medial tibial cartilage volume (B = −6.7 [95% confidence interval (95% CI) −12.9, −0.6], P = 0.03) and an increased rate of medial tibial cartilage volume loss (B = 0.06 [95% CI 0.01, 0.12], P = 0.03). There was a trend toward worsening of medial tibiofemoral BMLs in relation to increased popliteal artery wall thickness (odds ratio 1.07 [95% CI 0.99, 1.15]; P = 0.07). No significant associations with the lateral tibiofemoral compartment were observed. Conclusion Increased popliteal artery wall thickness was associated with adverse changes in knee structure, as evidenced by reduced medial tibial cartilage volume, increased rate of cartilage volume loss, and a trend toward worsening of BMLs over 2 years. These findings suggest an association between vascular pathology and early structural changes in the knee, which supports the hypothesis that vascular health may play a role in the development of knee OA. [ABSTRACT FROM AUTHOR]

Objective The increased prevalence of osteoarthritis (OA) in postmenopausal women suggests that changes in either circulating sex steroid concentrations or the tissue response to sex steroids may have a role in the pathogenesis of OA. The aim of this study was to examine whether circulating sex steroid concentrations are associated with the incidence of total knee and total hip replacement for OA. Methods Study subjects (n = 2,621; all women) were recruited in 1990-1994 from the Melbourne Collaborative Cohort Study (MCCS). Circulating sex steroid concentrations were measured in blood samples obtained from the women at the time of recruitment. The incidence of total knee and total hip replacement for OA during 2001-2011 was determined by linking the MCCS records to the Australian Orthopaedic Association National Joint Replacement Registry. Results During the followup period, 115 women had undergone total knee replacement and 99 had undergone total hip replacement for OA. Greater log-transformed concentrations of estradiol were associated with a lower incidence of knee replacement (hazard ratio [HR] 0.70, 95% confidence interval [95% CI] 0.50-0.96), and greater log-transformed concentrations of androstenedione were associated with a lower incidence of hip replacement (HR 0.70, 95% CI 0.52-0.93). In contrast, greater log-transformed concentrations of sex hormone binding globulin (SHBG) were associated with a higher incidence of hip replacement (HR 1.70, 95% CI 1.05-2.77). Conclusion A lower estradiol concentration is a risk factor for knee OA, while a lower androstenedione concentration and higher SHBG concentration are risk factors for hip OA in women. These findings suggest that circulating sex steroids have a role in the pathogenesis of OA, and that modifying these steroid concentrations may provide a potential strategy for the prevention and treatment of knee and hip OA. [ABSTRACT FROM AUTHOR]

Objective. The data are conflicting for the association between the index-to-ring finger length ratio (2D:4D) and the risk of OA. The aim of this cohort study was to examine the relationship between 2D:4D and the risk of severe knee and hip OA requiring total joint replacement.Methods. A total of 14 511 participants in the Melbourne Collaborative Cohort Study had 2D:4D assessed from hand photocopies. The incidence of total knee replacement and total hip replacement between 2001 and 2011 was determined by linking the cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.Results. Over an average 10.5 years of follow-up, 580 participants had total knee replacement and 499 had total hip replacement. Greater right 2D:4D [hazard ratio (HR) 0.91 for a s.d. increase in 2D:4D, 95% CI 0.84, 0.99, P = 0.03] and average right and left 2D:4D (HR 0.91 for a s.d. increase in 2D:4D, 95% CI 0.84, 0.99, P = 0.02) were associated with a reduced incidence of total knee replacement. These associations persisted when participants whose fingers had any features that might have affected the validity of 2D:4D measurements were excluded. No significant associations were observed between 2D:4D and the incidence of total hip replacement.Conclusion. A lower 2D:4D is associated with an increased risk of severe knee OA requiring total knee replacement, but not the risk of severe hip OA. The underlying mechanisms for the association warrant further investigation. [ABSTRACT FROM PUBLISHER]

Objectives. To examine the relationships between weight at early and middle adulthood and adult weight gain and the risk of total knee and hip replacement for OA.Methods. At baseline interview during 1990–94, 38 149 participants [mean age 54.9 (s.d. 8.6) years] of the Melbourne Collaborative Cohort Study were asked to recall their weight at age 18–21 years and had their middle age height and weight measured. Total knee and hip replacement for OA between 2001 and 2009 was determined by linking the cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.Results. Greater weight and BMI at age 18–21 years and middle age, weight gain and persistent overweight during this time were associated with an increased risk of total knee and hip replacement. Middle age weight [hazard ratio (HR) per 5 kg 1.25 (95% CI 1.23, 1.27) for knee vs 1.11 (1.09, 1.14) for hip] and BMI [HR per 5 kg/m2 1.80 (1.72, 1.89) vs 1.29 (1.21, 1.37)] and adult weight gain [HR per 5 kg 1.25 (1.23, 1.28) vs 1.10 (1.07, 1.13)] were more strongly associated with the risk of total knee replacement than total hip replacement (P for heterogeneity of HRs <0.0001).Conclusion. Greater body weight and BMI at early and middle adulthood, weight gain and persistent overweight from early to middle adulthood are risk factors for knee and hip OA. Adult weight gain confers stronger risk on knee OA than hip OA. Weight control from early adulthood and avoiding weight gain are important for the prevention of OA. [ABSTRACT FROM PUBLISHER]

The article discusses research which was conducted to determine whether the angle of the trochlear groove is associated with the rate of loss of patella cartilage volume and whether this association is influenced by particular modifiable and nonmodifiable factors. Researchers evaluated 297 people with no history of knee pathologic disease. They found that a more flattened proximal trochlear groove is associated with increased patella cartilage volume loss, particularly for physically active men, and that that lifestyle factors, such as physical activity, may modify the association between joint incongruity and cartilage loss and can be further affected by subjects' characteristics such as gender.