Metformin's role in lowering colorectal cancer risk among individuals with diabetes from the Southern Community Cohort Study.

BACKGROUND: Metformin, utilized to manage hyperglycemia, has been linked to a reduced risk of colorectal cancer (CRC) among individuals with diabetes. However, evidence is lacking for non-Hispanic Black individuals and those with lower socioeconomic status (SES), who face elevated risk for both diabetes and CRC. In this study, we investigated the association between metformin use and incident CRC risk within the Southern Community Cohort Study (SCCS), a racially- and SES-diverse prospective cohort. METHODS: Participants reported their diabetes diagnosis and medications, including metformin, upon enrollment (2002-2009) and during follow-up surveys approximately every five years. Incident cases of CRC were identified through state cancer registries and the National Death Index. Proportional hazards models were employed to explore the relationship between metformin use and CRC risk, adjusted for cancer risk factors. RESULTS: A total of 25,992 participants with diabetes were included in the analysis, among whom 10,095 were taking metformin. Of these participants, 76% identified as non-Hispanic Black, and 60% reported household incomes <$15,000/year. Metformin use was associated with a significantly lower CRC risk (HR [95% CI]: 0.71 [0.55-0.93]), with consistent results for both colon (0.80 [0.59-1.07]) and rectal cancers (0.49 [0.28-0.86]). The protective association appeared to be stronger among non-Hispanic White individuals (0.51 [0.31-0.85]) compared to non-Hispanic Black participants (0.80 [0.59-1.08], p-interaction =.13). Additionally, a protective association was observed among obese individuals (BMI ≥30 kg/m2, 0.59 [0.43-0.82] but not among non-obese participants (0.99 [0.65-1.51], p-interaction =.05) CONCLUSION: Our findings indicate that metformin use is associated with a reduced risk of CRC in individuals with diabetes, including among those from predominantly low SES backgrounds. These results support previous epidemiological findings, and demonstrate that the protective association for metformin in relation to incident CRC likely generalizes to populations with higher underlying risk.

Type 2 Diabetes and Colorectal Cancer Risk.

Importance: Type 2 diabetes and colorectal cancer (CRC) disproportionately burden indviduals of low socioeconomic status and African American race. Although diabetes is an emerging CRC risk factor, associations between diabetes and CRC in these populations are understudied. Objective: To determine if diabetes is associated with CRC risk in a cohort representing understudied populations. Design, Setting, and Participants: This cohort study uses data from the prospective Southern Community Cohort Study in the US, which recruited from 2002 to 2009 and completed 3 follow-up surveys by 2018. Of about 85 000 participants, 86% enrolled at community health centers, while 14% were enrolled via mail or telephone from the same 12 recruitment states. Participants with less than 2 years of follow-up, previous cancer diagnosis (excluding nonmelanoma skin cancer) at enrollment, missing enrollment diabetes status, diabetes diagnosis before age 30, and without diabetes at enrollment with no follow-up participation were excluded. Data were analyzed from January to September 2023. Exposures: Physician-diagnosed diabetes and age at diabetes diagnosis were self-reported via survey at enrollment and 3 follow-ups. Main Outcomes and Measures: Diabetes diagnosis was hypothesized to be positively associated with CRC risk before analysis. Incident CRC was assessed via state cancer registry and National Death Index linkage. Hazard ratios and 95% CIs were obtained via Cox proportional hazard models, using time-varying diabetes exposure. Results: Among 54 597 participants, the median (IQR) enrollment age was 51 (46-58) years, 34 786 (64%) were female, 36 170 (66%) were African American, and 28 792 (53%) had income less than $15 000 per year. In total, 289 of 25 992 participants with diabetes developed CRC, vs 197 of 28 605 participants without diabetes. Diabetes was associated with increased CRC risk (hazard ratio [HR], 1.47; 95% CI, 1.21-1.79). Greater associations were observed among participants without colonoscopy screening (HR, 2.07; 95% CI, 1.16-3.67) and with smoking history (HR, 1.62; 95% CI, 1.14-2.31), potentially due to cancer screening differences. Greater associations were also observed for participants with recent diabetes diagnoses (diabetes duration <5 years compared with 5-10 years; HR, 2.55; 95% CI, 1.77-3.67), possibly due to recent screening. Conclusions and Relevance: In this study where the majority of participants were African American with low socioeconomic status, diabetes was associated with elevated CRC risk, suggesting that diabetes prevention and control may reduce CRC disparities. The association was attenuated for those who completed colonoscopies, highlighting how adverse effects of diabetes-related metabolic dysregulation may be disrupted by preventative screening.

Behavioural interventions for CVD risk reduction for blue-collar workers: a systematic review.

OBJECTIVES: Individuals working in blue-collar occupations experience high rates of cardiovascular disease (CVD). The purpose of this systematic review is to describe the characteristics and efficacy of behavioural interventions that have targeted CVD risk factors in this high-risk group. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched seven databases to find interventions focused on changing the following: blood pressure, cholesterol, diet, physical activity, smoking or weight. Eligible studies tested a behavioural intervention (not exclusively policy, environmental, or pharmaceutical), in individuals working in blue-collar occupations using a randomised study design. Study quality was evaluated using the National Heart, Lung, and Blood Institute's study quality assessment tool. RESULTS: 22 studies evaluating 31 interventions were included: 11 were rated as 'good' or 'fair' quality. Intervention intensity ranged from a single contact via a mailed letter to studies that included individual-level contacts at multiple time points between staff and participants. Studies that included at least some individual contact generally yielded the greatest effects. Interventions had the greatest observed effects on self-report changes in diet, regardless of intervention intensity. Four of the five higher quality studies that explicitly tailored the intervention to the occupational group were successful at reducing at least one risk factor. CONCLUSIONS: Interventions that used individual contact and tailored the intervention to the occupational setting yielded the greatest effects on CVD risk-factor reduction in individuals working in blue-collar occupations. Generally, studies were low quality but showed promising effects for reaching this high-risk population. Future work should incorporate these promising findings in higher quality studies. PROSPERO REGISTRATION NUMBER: CRD42019136183.

The influence of the number of part-set cues on order retention.

Across seven experiments, the present article examined the influence of the number of part-set cues on order retention, as assessed by both reconstruction of order and serial recall tests. Historically, part-set cueing facilitation occurs when half of the items are provided as valid part-set cues on tests of order memory. Using a variety of list lengths (10 or 16), numbers of cues (0-14), and types of cues (full or partial), the present experiments showed disparate effects of the number of part-set cues on reconstruction and serial recall tasks. On reconstruction tests, a minimum number of full cues was required before part-set cueing facilitation was produced and the magnitude of facilitation increased as the number of cues increased. Generally, partial cues did not influence order retention until almost the entire list was provided as partial cues. On serial recall tests, part-set cueing facilitation was only evident with a few full cues. In contrast, part-set cueing impairment was the norm when many partial cues were provided. These results were largely consistent with predictions of the retrieval strategy disruption hypothesis, as well as with an anchoring account of part-set cueing for order.