Dairy consumption and incident prediabetes: prospective associations and network models in the large population-based Lifelines Study

BACKGROUND

Evidence on associations between dairy consumption and incident prediabetes is inconsistent. One potential explanation for heterogeneity is that health behavior and food intake covary with the consumption of various high-fat and low-fat dairy types.

OBJECTIVE

The objective was to investigate the associations of total dairy and dairy types with incident prediabetes and to assess how dairy intake is linked with metabolic risk factors, lifestyle behaviors, and foods, as potential explanations for these associations.

METHODS

Overall, 74,132 participants from the prospective population-based Lifelines study were included (mean age, 45.5 ± 12.3 y; 59.7% female). Baseline dairy intake was measured using a validated food frequency questionnaire. Prediabetes at follow-up was defined based on the World Health Organization/International Expert Committee criteria as fasting plasma glucose of 110-125 mg/dL or glycated hemoglobin concentrations of 6.0%-6.5%. Associations were analyzed using Poisson regression models adjusted for social demographics, lifestyle behaviors, family history of diabetes, and food group intake. Interconnections were assessed with mixed graphical model networks.

RESULTS

At a mean follow-up of 4.1 ± 1.1 y, 2746 participants developed prediabetes (3.7%). In regression analyses, neutral associations were found for most dairy types. Intake of plain milk and low-fat milk were associated with a higher risk of prediabetes in the top compared with bottom quartiles (relative risk [RR]: 1.17; 95% confidence interval [CI]: 1.05, 1.30; P-trend = 0.04 and RR: 1.18; 95% CI: 1.06, 1.31; P-trend =0.01). Strong but nonsignificant effect estimates for high-fat yogurt in relation to prediabetes were found (RRservings/day: 0.80; 95% CI: 0.64, 1.01). The network analysis showed that low-fat milk clustered with energy-dense foods, including bread, meat, and high-fat cheese, whereas high-fat yogurt had no clear link with lifestyle risk factors and food intake.

CONCLUSIONS

In this large cohort of Dutch adults, low-fat milk intake was associated with higher prediabetes risk. Heterogeneous associations by dairy type and fat content might partly be attributed to confounding caused by behaviors and food intake related to dairy intake.

Dairy product consumption and incident prediabetes in the Australian Diabetes, Obesity and Lifestyle Study with 12 years follow up

BACKGROUND

Investigating modifiable risk factors of early stages of the development of type 2 diabetes is essential for effective prevention. Some studies show protective associations between dairy and prediabetes, yet associations are heterogenous by type and fat content of dairy foods.

OBJECTIVE

To examine the relationship between the consumption of dairy, including different types of dairy products and the risk of prediabetes.

METHODS

The study included 4,891 participants with normal glucose tolerance (aged 49.0±12.3 years, 57% female) of the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, a longitudinal population-based study. Dairy intake was measured at baseline using a food frequency questionnaire. Prediabetes at 5-year and 12-year follow-up was defined according to WHO criteria as fasting plasma glucose levels of 110-125 mg/dl or 2-hour plasma glucose levels of 140-199 mg/dl. Associations were analyzed using Poisson regression, adjusted for social demographics, lifestyle behaviors, family history of diabetes, and food group intake.

RESULTS

765 (15.6%) incident cases of prediabetes were observed. The mean intake of dairy foods was 2.4±1.2 servings/day, mostly consisting of low-fat milk (0.70±0.78) and high-fat milk (0.47±0.72). A higher intake of high-fat dairy (RR_servings/day, 0.92, 95%CI 0.85-1.00), high-fat milk (0.89, 0.80-0.99), and total cheese (0.74, 0.56-0.96)was associated with lower prediabetes risk. Low-fat milk intake was associated non-linearly with prediabetes risk. Low-fat dairy foods, total milk, yogurt, low-fat cheese, and ice cream were not associated with prediabetes risk.

CONCLUSION

In this large Australian cohort, protective associations were found for high-fat dairy types, while neutral associations were seen for low-fat dairy. Studies with more detail on sugar content of types of dairy foods and products eaten with dairy foods (e.g., cereals or jam), as well as studies into potential causal mechanisms of the health effects of dairy intake are required.

Educational level and risk of sexually transmitted infections among clients of Dutch sexual health centres

This study aimed to assess whether educational level is an independent determinant for sexually transmitted infections (STIs) among clients consulting Dutch sexual health centres (SHCs). With data from the National STI surveillance database (2015-2017), generalized estimating equations corrected for (sexual) risk factors were used to estimate associations between educational level and chlamydia and gonorrhoea among women (n = 146,020), heterosexual men (n = 82,882) and men who have sex with men (MSM) (n = 52,149) and syphilis and HIV among MSM. Compared to the highest educational level (bachelor/master), all lower educational levels were associated with gonorrhoea among women (adjusted odds ratio 1.40; 95% CI 1.18-1.66 for higher general/pre-university level to 3.57; 95% CI 2.66-4.81 for no education/elementary school level) and heterosexual men (respectively 1.36; 1.06-1.74 to 3.84; 2.89-5.09). Women with no education/elementary school level (1.37; 1.17-1.62) and heterosexual clients with (pre-)vocational secondary educational level were more likely to test positive for chlamydia (women: 1.43; 1.39-1.48 and heterosexual men: 1.31; 1.26-1.37) than clients with higher general/pre-university level or bachelor/master level. In MSM, (pre-)vocational secondary educational level was associated with chlamydia (1.16; 1.11-1.22), gonorrhoea (1.15; 1.10-1.21) and syphilis (1.18; 1.08-1.29), and both (pre-)vocational secondary educational level (1.48; 1.25-1.76) and no education/elementary school level (1.81; 1.09-3.00) were associated with HIV. Lower educational levels were independent determinants of STI in SHC clients. Sexual health centres could facilitate STI testing and care among lower educated people by prioritizing their access.