Search

OBJECTIVE We evaluated prospectively the association between incident early-onset (diagnosed before 40 years of age) and later-onset type 2 diabetes and early-onset (diagnosed before 50 years of age) and later-onset cancer risk. RESEARCH DESIGN AND METHODS We prospectively followed 228,073 eligible participants in the Nurses’ Health Studies for up to 38 years. Hazard ratios (HRs) and 95% CI were estimated using Cox models. RESULTS We documented 18,290 type 2 diabetes, 6,520 early-onset cancer, and 36,907 later-onset cancer cases during follow-up. In fully adjusted analyses, early-onset type 2 diabetes was associated with increased risk of early-onset total cancer (HR [95% CI] 1.47 [1.06–2.04]), diabetes-related cancer (2.11 [1.38–3.23]), and obesity-related cancer (1.75 [1.08–2.82]), and the risk elevations were restricted to those with a BMI at 18 years of age of ≥21 kg/m2 (total cancer: 1.75 [1.20–2.56]; diabetes-related cancer: 2.43 [1.50–3.94]; and obesity-related cancer: 1.84 [1.05–3.22]). Early-onset type 2 diabetes was associated with higher risk of later-onset diabetes-related and obesity-related cancer specifically among individuals with higher BMI at 18 years of age. Later-onset type 2 diabetes was associated with a higher risk of later-onset total cancer (1.15 [1.11–1.20]), diabetes-related cancer (1.17 [1.12–1.22]), and obesity-related cancer (1.18 [1.13–1.24]). In analyses based on refined timing, the HRs attenuated substantially with aging. CONCLUSIONS Incident early-onset type 2 diabetes was associated with increased risk of early-onset total cancer and diabetes- and obesity-related cancer, especially in those with higher BMI at 18 years of age. The impact of early-onset type 2 diabetes on cancer risk may be inherently stronger than that of later-onset type 2 diabetes.

BACKGROUND Earlier evidence on the association between dietary polyunsaturated fatty acids and risk of diabetes has been conflicting. PURPOSE To quantitatively summarize previous studies on the association between dietary LA intake, its biomarkers, and the risk of type 2 diabetes mellitus (T2DM) in the general population. DATA SOURCES Our data sources included PubMed/MEDLINE, Scopus, and ISI Web of Science until 24 October 2020; reference lists of all related articles; and key journals. STUDY SELECTION We included prospective cohort studies that examined the associations of linoleic acid (LA) with the risk of T2DM in adults. DATA SYNTHESIS The inverse variance method was applied to calculate summary relative risk (RR) of LA intake and its biomarkers, and dose-response associations were modeled using restricted cubic splines. Twenty-three publications, covering a total of 31 prospective cohorts, were included; these studies included 297,685 participants (22,639 incident diabetes cases) with dietary intake assessment and 84,171 participants (18,458 incident diabetes cases) with biomarker measurements. High intake of LA was associated with a 6% lower risk of T2DM (summary relative risk [RR] 0.94, 95% CI 0.90, 0.99; I2 = 48.5%). In the dose-response analysis, each 5% increment in energy from LA intake was associated with a 10% lower risk of T2DM. There was also evidence of a linear association between LA intake and diabetes, with the lowest risk at highest intakes. The summary RR for diabetes per SD increment in LA concentrations in adipose tissue/blood compartments was 0.85 (95% CI 0.80, 0.90; I2 = 66.2%). The certainty of the evidence was assessed as moderate. LIMITATIONS A limitation of our work was the observational design of studies included in the analyses. CONCLUSIONS We found that a high intake of dietary LA and elevated concentrations of LA in the body were both significantly associated with a lower risk of T2DM. These findings support dietary recommendations to consume dietary LA.

OBJECTIVE Insulin response is related to overall health. Diet modulates insulin response. We investigated whether insulinemic potential of diet is associated with risk of all-cause and cause-specific mortality. RESEARCH DESIGN AND METHODS We prospectively followed 63,464 women from the Nurses’ Health Study (1986–2016) and 42,880 men from the Health Professionals Follow-up Study (1986–2016). Diet was assessed by food frequency questionnaires every 4 years. The insulinemic potential of diet was evaluated using a food-based empirical dietary index for hyperinsulinemia (EDIH), which was predefined based on predicting circulating C-peptide concentrations. RESULTS During 2,792,550 person-years of follow-up, 38,329 deaths occurred. In the pooled multivariable-adjusted analyses, a higher dietary insulinemic potential was associated with an increased risk of mortality from all-cause (hazard ratio [HR] comparing extreme quintiles: 1.33; 95% CI 1.29, 1.38; P-trend CONCLUSIONS Higher insulinemic potential of diet was associated with increased risk of all-cause, CVD, and cancer mortality. Adopting a diet with low insulinemic potential might be an effective approach to improve overall health and prevent premature death.

OBJECTIVE To investigate the association between intakes of n-6 polyunsaturated fatty acids (PUFAs) and type 2 diabetes risk in three prospective cohort studies of U.S. men and women. RESEARCH DESIGN AND METHODS We followed 83,648 women from the Nurses’ Health Study (NHS) (1980–2012), 88,610 women from NHSII (1991–2013), and 41,771 men from the Health Professionals Follow-Up Study (HPFS) (1986–2012). Dietary data were collected every 2–4 years by using validated food-frequency questionnaires. Self-reported incident diabetes, identified biennially, was confirmed by using a validated supplementary questionnaire. RESULTS During 4.93 million person-years of follow-up, 18,442 type 2 diabetes cases were documented. Dietary n-6 PUFAs accounted for 4.4–6.8% of total energy, on average, and consisted primarily of linoleic acid (LA) (≥98%). In multivariate-adjusted models, hazard ratios (95% CIs) of type 2 diabetes risk comparing extreme n-6 PUFA quintiles (highest vs. lowest) were 0.91 (0.85, 0.96) (Ptrend = 0.002) for total n-6 PUFAs and 0.92 (0.87, 0.98) (Ptrend = 0.01) for LA. In an isocaloric substitution model, diabetes risk was 14% (95% CI 5%, 21%) (P = 0.002) lower when LA isocalorically replaced saturated fats (5% of energy), 17% (95% CI 9%, 24%) (P < 0.001) lower for trans fats (2% of energy), or 9% (95% CI 17%, 0.1%) (P = 0.047) lower for carbohydrates (5% of energy). Replacing n-3 PUFAs or monounsaturated fats with LA was not significantly associated with type 2 diabetes risk. CONCLUSIONS Our study provides additional evidence that LA intake is inversely associated with risk of type 2 diabetes, especially when replacing saturated fatty acids, trans fats, or carbohydrates.

OBJECTIVE We evaluated the associations between changes in plant-based diets and subsequent risk of type 2 diabetes. RESEARCH DESIGN AND METHODS We prospectively followed 76,530 women in the Nurses’ Health Study (NHS) (1986–2012), 81,569 women in NHS II (1991–2017), and 34,468 men in the Health Professionals Follow-up Study (1986–2016). Adherence to plant-based diets was assessed every 4 years with the overall plant-based diet index (PDI), healthful PDI (hPDI), and unhealthful PDI (uPDI). We used multivariable Cox proportional hazards models to estimate hazard ratios (HRs). We pooled results of the three cohorts using meta-analysis. RESULTS We documented 12,627 cases of type 2 diabetes during 2,955,350 person-years of follow-up. After adjustment for initial BMI and initial and 4-year changes in alcohol intake, smoking, physical activity, and other factors, compared with participants whose indices remained relatively stable (±3%), participants with the largest decrease (>10%) in PDI and hPDI over 4 years had a 12–23% higher diabetes risk in the subsequent 4 years (pooled HR, PDI 1.12 [95% CI 1.05, 1.20], hPDI 1.23 [1.16, 1.31]). Each 10% increment in PDI and hPDI over 4 years was associated with a 7–9% lower risk (PDI 0.93 [0.91, 0.95], hPDI 0.91 [0.87, 0.95]). Changes in uPDI were not associated with diabetes risk. Weight changes accounted for 6.0–35.6% of the associations between changes in PDI and hPDI and diabetes risk. CONCLUSIONS Improving adherence to overall and healthful plant-based diets was associated with a lower risk of type 2 diabetes, whereas decreased adherence to such diets was associated with a higher risk.

OBJECTIVE To examine whether proinflammatory and hyperinsulinemic diets are associated with increased risk of type 2 diabetes. RESEARCH DESIGN AND METHODS We prospectively followed 74,767 women from the Nurses’ Health Study (1984–2016), 90,786 women from the Nurses’ Health Study II (1989–2017), and 39,442 men from the Health Professionals Follow-up Study (1986–2016). Using repeated measures of food-frequency questionnaires, we calculated empirical dietary inflammatory pattern (EDIP) and empirical dietary index for hyperinsulinemia (EDIH) scores, which are food-based indices that characterize dietary inflammatory or insulinemic potential based on circulating biomarkers of inflammation or C-peptide. Diagnoses of type 2 diabetes were confirmed by validated supplementary questionnaires. RESULTS We documented 19,666 incident type 2 diabetes cases over 4.9 million person-years of follow-up. In the pooled multivariable-adjusted analyses, individuals in the highest EDIP or EDIH quintile had 3.11 times (95% CI 2.96–3.27) and 3.40 times (95% CI 3.23–3.58) higher type 2 diabetes risk, respectively, compared with those in the lowest quintile. Additional adjustment for BMI attenuated the associations (hazard ratio 1.95 [95% CI 1.85–2.05] for EDIP and hazard ratio 1.87 [95% CI 1.78–1.98] for EDIH), suggesting adiposity partly mediates the observed associations. Moreover, individuals in both highest EDIP and EDIH quintiles had 2.34 times higher type 2 diabetes risk (95% CI 2.17–2.52), compared with those in both lowest quintiles, after adjustment for BMI. CONCLUSIONS Higher dietary inflammatory and insulinemic potential were associated with increased type 2 diabetes incidence. Findings suggest that inflammation and hyperinsulinemia are potential mechanisms linking dietary patterns and type 2 diabetes development.

OBJECTIVE Coffee may protect against multiple chronic diseases, particularly type 2 diabetes, but the mechanisms remain unclear. RESEARCH DESIGN AND METHODS Leveraging dietary and metabolomic data in two large cohorts of women (the Nurses’ Health Study [NHS] and NHSII), we identified and validated plasma metabolites associated with coffee intake in 1,595 women. We then evaluated the prospective association of coffee-related metabolites with diabetes risk and the added predictivity of these metabolites for diabetes in two nested case-control studies (n = 457 case and 1,371 control subjects). RESULTS Of 461 metabolites, 34 were identified and validated to be associated with total coffee intake, including 13 positive associations (primarily trigonelline, polyphenol metabolites, and caffeine metabolites) and 21 inverse associations (primarily triacylglycerols [TAGs] and diacylglycerols [DAGs]). These associations were generally consistent for caffeinated and decaffeinated coffee, except for caffeine and its metabolites that were only associated with caffeinated coffee intake. The three cholesteryl esters positively associated with coffee intake showed inverse associations with diabetes risk, whereas the 12 metabolites negatively associated with coffee (5 DAGs and 7 TAGs) showed positive associations with diabetes. Adding the 15 diabetes-associated metabolites to a classical risk factor–based prediction model increased the C-statistic from 0.79 (95% CI 0.76, 0.83) to 0.83 (95% CI 0.80, 0.86) (P < 0.001). Similar improvement was observed in the validation set. CONCLUSIONS Coffee consumption is associated with widespread metabolic changes, among which lipid metabolites may be critical for the antidiabetes benefit of coffee. Coffee-related metabolites might help improve prediction of diabetes, but further validation studies are needed.

OBJECTIVE To examine open-flame and/or high-temperature cooking (grilling/barbecuing, broiling, or roasting) and doneness preferences (rare, medium, or well done) for red meat, chicken, and fish in relation to type 2 diabetes (T2D) risk among U.S. adults who consumed animal flesh regularly (≥2 servings/week). RESEARCH DESIGN AND METHODS The prospective studies included 52,752 women from the Nurses’ Health Study (NHS) (followed during 1996–2012), 60,809 women from NHS II (followed during 2001–2013), and 24,679 men from the Health Professionals Follow-Up Study (HPFS) (followed during 1996–2012) who were free of diabetes, cardiovascular disease, and cancer at baseline. Incident cases of T2D were confirmed by validated supplementary questionnaires. RESULTS We documented 7,895 incident cases of T2D during 1.74 million person-years of follow-up. After multivariate adjustments including baseline BMI and total consumption of red meat, chicken, and fish, higher frequency of open-flame and/or high-temperature cooking was independently associated with an elevated T2D risk. When comparing open-flame and/or high-temperature cooking >15 times/month with CONCLUSIONS Independent of consumption amount, open-flame and/or high-temperature cooking for both red meat and chicken is associated with an increased T2D risk among adults who consume animal flesh regularly.

OBJECTIVE We evaluated the associations of long-term changes in consumption of sugary beverages (including sugar-sweetened beverages and 100% fruit juices) and artificially sweetened beverages (ASBs) with subsequent risk of type 2 diabetes. RESEARCH DESIGN AND METHODS We followed up 76,531 women in the Nurses’ Health Study (1986–2012), 81,597 women in the Nurses’ Health Study II (1991–2013), and 34,224 men in the Health Professionals’ Follow-up Study (1986–2012). Changes in beverage consumption (in 8-ounce servings/day) were calculated from food frequency questionnaires administered every 4 years. Multivariable Cox proportional regression models were used to calculate hazard ratios for diabetes associated with changes in beverage consumption. Results of the three cohorts were pooled using an inverse variance–weighted, fixed-effect meta-analysis. RESULTS During 2,783,210 person-years of follow-up, we documented 11,906 incident cases of type 2 diabetes. After adjustment for BMI and initial and changes in diet and lifestyle covariates, increasing total sugary beverage intake (including both sugar-sweetened beverages and 100% fruit juices) by >0.50 serving/day over a 4-year period was associated with a 16% (95% CI 1%, 34%) higher diabetes risk in the subsequent 4 years. Increasing ASB consumption by >0.50 serving/day was associated with 18% (2%, 36%) higher diabetes risk. Replacing one daily serving of sugary beverage with water, coffee, or tea, but not ASB, was associated with a 2–10% lower diabetes risk. CONCLUSIONS Increasing consumption of sugary beverages or ASBs was associated with a higher risk of type 2 diabetes, albeit the latter association may be affected by reverse causation and surveillance bias.

OBJECTIVE We aimed to elucidate whether potato consumption is associated with a higher risk of type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS We analyzed data in three cohorts consisting of U.S. male and female health professionals without diabetes, cardiovascular disease, and cancer at baseline: 70,773 women from the Nurses’ Health Study (1984–2010), 87,739 women from Nurses’ Health Study II (1991–2011), and 40,669 men from the Health Professionals Follow-up Study (1986–2010). Potato consumption was assessed quadrennially using validated food frequency questionnaires (FFQs), and we calculated 4-year change in potato consumption from consecutive FFQs. Self-reported T2D diagnosis was confirmed using a validated supplementary questionnaire. RESULTS During 3,988,007 person-years of follow-up, 15,362 new cases of T2D were identified. Higher consumption of total potatoes (including baked, boiled, or mashed potatoes and french fries) was significantly associated with an elevated risk for T2D: the pooled hazard ratio (HR) of T2D compared with CONCLUSIONS Greater consumption of potatoes, especially french fries, was associated with a higher T2D risk, independent of BMI and other risk factors. Replacement of potatoes with whole grains was associated with a lower T2D risk.