Responses of grape berry anthocyanin and titratable acidity to the projected climate change across the Western Australian wine regions

More than a century of observations has established that climate influences grape berry composition. Accordingly, the projected global climate change is expected to impact on grape berry composition although the magnitude and direction of impact at regional and subregional scales are not fully known. The aim of this study was to assess potential impacts of climate change on levels of berry anthocyanin and titratable acidity (TA) of the major grapevine varieties grown across all of the Western Australian (WA) wine regions. Grape berry anthocyanin and TA responses across all WA wine regions were projected for 2030, 2050 and 2070 by utilising empirical models that link these berry attributes and climate data downscaled (to ～5 km resolution) from the csiro_mk3_5 and miroc3_2_medres global climate model outputs under IPCC SRES A2 emissions scenario. Due to the dependence of berry composition on maturity, climate impacts on anthocyanin and TA levels were assessed at a common maturity of 22 °Brix total soluble solids (TSS), which necessitated the determination of when this maturity will be reached for each variety, region and warming scenario, and future period. The results indicate that both anthocyanin and TA levels will be affected negatively by a warming climate, but the magnitude of the impacts will differ between varieties and wine regions. Compared to 1990 levels, median anthocyanins concentrations are projected to decrease, depending on global climate model, by up to 3–12 % and 9–33 % for the northern wine regions by 2030 and 2070, respectively while 2–18 % reductions are projected in the southern wine regions for the same time periods. Patterns of reductions in the median Shiraz berry anthocyanin concentrations are similar to that of Cabernet Sauvignon; however, the magnitude is lower (up to 9–18 % in southern and northern wine regions respectively by 2070). Similarly, uneven declines in TA levels are projected across the study regions. The largest reductions in median TA are likely to occur in the present day warmer wine regions, up to 40 % for Chardonnay followed by 15 % and 12 % for Shiraz and Cabernet Sauvignon, respectively, by 2070 under the high warming projection (csiro_mk3_5). It is concluded that, under existing management practices, some of the key grape attributes that are integral to premium wine production will be affected negatively by a warming climate, but the magnitudes of the impacts vary across the established wine regions, varieties, the magnitude of warming and future periods considered.     

BMI Compared With Central Obesity Indicators as a Predictor of Diabetes Incidence in Mauritius

The aim of the study was to compare BMI with waist circumference (WC), waist‐to‐hip ratio (WHR), and waist‐to‐stature ratio (WSR) as a predictor of diabetes incidence. A total of 1,841 men and 2,104 women of Mauritian Indian and Mauritian Creole ethnicity, aged 25–74 years, free of diabetes, hypertension, cardiovascular disease, and gout were seen at baseline in 1987 or 1992, and follow‐up in 1992 and/or 1998. At all time points, participants underwent a 2 h 75 g oral glucose tolerance test. Hazard ratios for diabetes incidence were estimated applying an interval‐censored survival analysis using age as timescale. Six hundred and twenty‐eight individuals developed diabetes during the follow‐up period. Multivariable adjusted hazard ratios for diabetes incidence corresponding to a 1 s.d. increase in baseline BMI, WC, WHR, and WSR for Mauritian Indians were 1.49 (1.31–1.71), 1.58 (1.38–1.81), 1.54 (1.37–1.72), and 1.61 (1.41–1.84) in men and 1.33 (1.17–1.51), 1.35 (1.19–1.53), 1.39 (1.24–1.55), and 1.38 (1.21–1.57) in women, respectively; and for Mauritian Creoles they were 1.86 (1.51–2.30), 2.07 (1.68–2.56), 1.92 (1.62–2.26), and 2.17 (1.76–2.69) in men and 1.29 (1.06–1.55), 1.27 (1.04–1.55), 1.24 (1.04–1.48), and 1.27 (1.04–1.55) in women. Paired homogeneity tests showed that there was no difference between BMI and each of the central obesity indicators (all P > 0.05). The relation of BMI with the development of diabetes was as strong as that for indicators of central obesity in this study population.     

BMI compared with central obesity indicators in relation to diabetes and hypertension in Asians

Objective: To compare BMI with waist circumference (WC), waist‐to‐hip ratio (WHR), and waist‐to‐stature ratio (WSR) in association with diabetes or hypertension. Methods and Procedures: Cross‐sectional data from 16 cohorts from the DECODA (Diabetes Epidemiology: Collaborative Analysis of Diagnostic criteria in Asia) study, comprising 9,095 men and 11,732 women, aged 35–74 years, of different ethnicities were included in this meta‐analysis. Results: Age‐adjusted odds ratios (ORs) for diabetes in men (women) for 1 s.d. increase in BMI, WC, WHR, and WSR were 1.52 (1.59), 1.54 (1.70), 1.53 (1.50), and 1.62 (1.70), respectively; and the corresponding ORs for hypertension were 1.68 (1.55), 1.66 (1.51), 1.45 (1.28), and 1.63 (1.50). Paired homogeneity tests (BMI with each of the three) adjusted for age and cohort showed that diabetes had stronger association with WSR than BMI (P = 0.001) in men but with WC and WSR than BMI (both P < 0.05) in women. Hypertension had stronger association with BMI than WHR in men (P < 0.001) and had the strongest with BMI than the others (WHR P < 0.001; WSR P < 0.01; and WC P < 0.05) in women. Areas under the receiver operating characteristic (ROC) curves adjusted for age and cohort were slightly larger for diabetes for WSR 0.735 (0.748) in men (women) and WC 0.749 (women only) than BMI 0.725 (0.742) while for hypertension larger for BMI 0.760 (0.766) than WHR 0.748 (0.751), but their 95% CIs were all overlapped. Discussion: WSR was stronger than BMI in association with diabetes, but these indicators were equally strongly associated with hypertension in Asians.     

Berry composition and climate: responses and empirical models

Climate is a strong modulator of berry composition. Accordingly, the projected change in climate is expected to impact on the composition of berries and of the resultant wines. However, the direction and extent of climate change impact on fruit composition of winegrape cultivars are not fully known. This study utilised a climate gradient along a 700 km transect, covering all wine regions of Western Australia, to explore and empirically describe influences of climate on anthocyanins, pH and titratable acidity (TA) levels in two or three cultivars of Vitis vinifera (Cabernet Sauvignon, Chardonnay and Shiraz). The results showed that, at a common maturity of 22° Brix total soluble solids, berries from the warmer regions had low levels of anthocyanins and TA as well as high pH compared to berries from the cooler regions. Most of these regional variations in berry composition reflected the prevailing climatic conditions of the regions. Thus, depending on cultivar, 82–87 % of TA, 83 % of anthocyanins and about half of the pH variations across the gradient were explained by climate-variable-based empirical models. Some of the variables that were relevant in describing the variations in berry attributes included: diurnal ranges and ripening period temperature (TA), vapour pressure deficit in October and growing degree days (pH), and ripening period temperatures (anthocyanins). Further, the rates of change in these berry attributes in response to climate variables were cultivar dependent. Based on the observed patterns along the climate gradient, it is concluded that: (1) in a warming climate, all other things being equal, berry anthocyanins and TA levels will decline whereas pH levels will rise; and (2) despite variations in non-climatic factors (e.g. soil type and management) along the sampling transect, variations in TA and anthocyanins were satisfactorily described using climate-variable-based empirical models, indicating the overriding impact of climate on berry composition. The models presented here are useful tools for assessing likely changes in berry TA and anthocyanins in response to changing climate for the wine regions and cultivars covered in this study.