Umeå University's logo

Objectives: The objectives were to: (i) assess the accuracy of dental data for adults obtained from the Swedish Quality Register on Caries and Periodontitis (SKaPa); (ii) explore whether Latent Class Analysis (LCA) can identify groups of people based on caries data; and (iii) characterise the dental, medical and behavioural characteristics of people in the LCA-derived classes.

Methods: Caries data from the SKaPa register were compared with clinical data collected by five experienced dentists in a nested subgroup of the Malmö Offspring Study (MOS), namely the Malmö Offspring Dental Study (MODS) (n = 724) for validation. Dental data from SKaPa were then used to classify 61 984 adult participants of the Västerbotten Intervention Programme (VIP) into five classes using LCA and DMFS-based quintile ranking, respectively. Dental status (including caries progression over 5 years), medical, anthropometric and behavioural characteristics were compared between the groups. Analyses were replicated in 2767 adults in the MOS.

Results: DMFS-scores and number of teeth recorded within −2 to +2 years showed excellent agreement between the SKaPa and reference data with intra-class correlations > 0.90. The five LCA classes differed in mean DMFS from 10.0 to 94.4. There were strong associations between LCA class and health, and health and behavioural measures respectively, including some associations that were not detected using DMFS-ranked quintile groups. LCA class was associated with incremental change in DMFS, DFS, and number of teeth. The results in the MOS cohort were consistent with the results in the VIP cohort.

Conclusions: Dental data for adults from the SKaPa registry were considered accurate within 2 years of recording. The LCA approach can classify participants into caries subtypes based on dental charting. These groups differ in health and behavioural characteristics and future caries increment. The LCA approach may capture some information that is missing from DMFS-ranked quintile groups, but is also heavily influenced by total DMFS, meaning that applying LCA in cumulative, highly age-determined diseases, such as caries, is a challenge.

Background/Objectives: We examined the association between dietary intake and blood concentrations of one-carbon metabolism (OCM)-related nutrients in the European Prospective Investigation into Cancer and Nutrition (EPIC).

Methods: Blood concentrations and dietary intake of the vitamins riboflavin (B2), Pyridoxal 5′-phosphate (PLP and B6), folate (B9), B12, and methionine, concentrations of homocysteine, and dietary intake of betaine, choline, and cysteine were pooled from 16,267 participants in nine EPIC nested case–control studies. Correlation analyses between dietary intakes and blood concentrations were carried out. Principal component (PC) analysis identified latent factors in the two sets of measurements.

Results: Pearson correlations between dietary intakes and blood concentrations ranged from 0.08 for methionine to 0.12 for vitamin B2, 0.15 for vitamin B12, 0.17 for vitamin B6, and 0.19 for folate. Individual dietary intakes showed higher correlations (ranging from −0.14 to 0.82) compared to individual blood concentrations (from −0.31 to 0.29). Correlations did not vary by smoking status, case–control status, or vitamin supplement use. The first PC of dietary intakes was mostly associated with methionine, vitamin B12, cysteine, and choline, while the first PC of blood concentrations was associated with folate and vitamin B6.

Conclusions: Within this large European study, we found weak to moderate associations between dietary intakes and concentrations of OCM-related nutrients.

Key features: 

• The Northern Sweden Health and Disease Study (NSHDS) was initiated in the mid-1980s. The NSHDS is a population-based prospective longitudinal cohort comprising >140 000 participants in the two northernmost regions in Sweden, Norrbotten and Västerbotten, with >240 000 blood samples and 1.5 million person-years of follow-up.
• The NSHDS includes three sub-cohorts: the Västerbotten Intervention Programme (VIP), the expanded Northern Sweden Monitoring of Trends and Determinants of Cardiovascular Disease (MONICA) Study, and the Mammography Screening Project (MSP). The VIP is both a community-based cardiometabolic intervention programme encouraging healthy lifestyle (targeting individuals 40, 50, and 60 years of age), and a corresponding research cohort. The MONICA is an observational study focusing on cardiovascular disease and its associated risk factors, recruiting individuals aged 25–74 years. The MSP recruited women attending mammography during 1995–2006. The NSHDS median participation age is 50 years (53% women).
• Most participants contribute data on health, lifestyle, anthropometric measures, blood pressure, blood lipids, and glucose tolerance, along with research blood samples that are fractionated, frozen within an hour of collection, and stored at –80°C. Linkage to registries, clinical cohorts, and biological tissue archives facilitates studies of well-characterized participants (often combined with intervention studies).
• Collaborations are encouraged. Additional information can be found at: info.brs@umu.se; https://www.umu.se/en/biobank

Background: High dietary diversity is recognized as a crucial element of diet quality because this ensures abundant nutrients. A diverse diet may also provide health benefits beyond nutritional adequacy. Few studies have evaluated associations with lipid profile. The aim of this study was to investigate the association between dietary diversity and metabolic health and common measures of diet quality in a large population-based sample.

Methods: This was a cross-sectional analysis within the V & auml;sterbotten Intervention Programme (VIP). Participants filled out an extensive health questionnaire including a 66-item semi-quantitative food frequency questionnaire (FFQ). The FFQ was used to create dietary diversity scores (DDS) for 5 major and 13 minor food groups. Associations between DDS and concurrent fasting lipid profile and measured body mass index (BMI) were explored with multivariable linear regression. Correlation analyses were used to explore the relationship between DDS and diet quality.

Results: The mean age of participants was 51 +/- 8.3 years, with females comprising 50.8% of the study population (n = 82,171). Higher DDS was associated with decreased total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides (all p < 0.01). DDS had no significant association with BMI. DDS had a positive correlation with the Relative Mediterranean Diet Score, the Healthy Nordic Food Index and the Healthy Diet Score, and a negative correlation with the Dietary Inflammatory Index (all p < 0.001).

Conclusion: The results add to the body of research showing metabolic health benefits of dietary diversity. More consistent methods of measuring dietary diversity should be developed, with careful consideration given to the healthfulness of foods included in the definition.

Introduction: Infant formulas with reduced iron levels and lactoferrin (Lf) supplementation might mimic the beneficial effects of breast milk on the oral microbiome. This study aimed to investigate the impact of a bovine Lf-supplemented and iron-reduced formula on the oral microbiota in infants at 4, 6 and 12 months.

Methods: In a double-blind controlled trial, 6-week-old formula-fed infants were randomized to receive either a formula with reduced iron levels (2 mg/L) and Lf supplementation (1 g/L) (n = 72), the same formula without Lf (n = 72), or a standard formula (8 mg iron/L) (n = 36). A breast-fed reference group (n = 72) was also included. The oral microbiota was analyzed at 4 (n = 244), 6 (n = 216) and 12 (n = 229) months of age using the Oxford Nanopore Technology of the 16S rRNA gene annotation (eHOMD database).

Results: Neither the within- or between-group diversities nor overall microbiota pattern assessment revealed any statistically significant differences in microbiota composition between the formula groups. However, single species were significantly associated with specific formula-fed groups. At 6 months, breast-fed infants exhibited significantly lower species richness and distinct microbiota composition compared to the formula-fed groups.

Conclusions: The effects of reduced iron levels and lactoferrin supplementation of infant formula on the oral microbiome were inconclusive.

Background: Maternal diet during pregnancy is considered a potential modifiable risk factor for allergic diseases in offspring. The dietary inflammatory index (DII) is a tool to assess the inflammatory potential of the diet and has been suggested to be associated with offspring allergy development. Its association with food allergy and immunoglobulin E (IgE) sensitization in children remains understudied.

Methods: This study analyzed 4709 mother-partner-child triads from the NorthPop Birth Cohort in Sweden. Maternal DII scores were calculated from a food frequency questionnaire administered at gestational week 34. Allergy outcomes at 18 months included parent-reported physician-diagnosed food allergy, parent-reported eczema and atopic eczema according to UK Working Party criteria, parent-reported ever wheeze, parent-reported physician-diagnosed asthma, and IgE sensitization to food and airborne allergens. Associations between maternal DII scores (continuous and quartiles) and allergic outcomes were assessed using logistic regression, adjusting for maternal age, allergic heredity, farm living, region of birth, siblings, and education.

Results: At age 18 months, 4.9% of children had physician-diagnosed food allergy, 30.6% had eczema, 11.4% had atopic eczema, 15.9% reported ever wheeze, 4.1% had physician-diagnosed asthma, and 19% were IgE sensitized. No significant associations were found between maternal DII scores and the allergic outcomes of interest.

Conclusion: This large birth cohort study found no association between maternal DII during pregnancy and allergic diseases or IgE sensitization in 18-month-old children, suggesting that a proinflammatory diet during pregnancy does not influence early allergic outcomes. Further research is needed to clarify the role of maternal diet in offspring immune development.

Background/Objectives: Trimethylamine N-oxide (TMAO), a gut microbiota-derived metabolite from L-carnitine and choline (abundant in meat and eggs), is linked to CVD and T2D. This study investigated whether TMAO responses to animal-based foods differ between individuals with and without metabolic syndrome (MetS), in relation to their gut microbiota composition.

Subjects/Methods: In a randomized crossover trial, 12 MetS (≥3 criteria according to the Adult Treatment Panel III: elevated waist circumference, fasting glucose, triglycerides, and blood pressure or reduced HDL cholesterol) and 21 non-MetS subjects consumed two test meals (3 hard-boiled eggs or 170 g meat balls) after overnight fasting, with ≥1-week washout. Blood was collected at baseline and 0.5, 1, 2, 4, and 6 h postprandially; urine was collected over 6 h. Fecal samples (collected pre-first day of intervention) underwent 16S rRNA sequencing. Plasma and urinary TMAO, TMA, choline, and carnitine were quantified using UPLC-MS/MS.

Results: MetS subjects exhibited a non-significant trend towards higher incremental AUCs for plasma TMA, TMAO, choline, and carnitine after consuming both foods, with a 30–50% higher urinary TMAO excretion (but similar for TMA) versus non-MetS subjects. This exploratory analysis also indicated that MetS subjects had reduced gut microbial diversity, featuring decreased Blautia glucerasea (butyrate producer) and increased Ruminococcus torques (pro-inflammatory), a profile associated with inflammation but not TMA production.

Conclusion: No significant increase in plasma methylamines after choline and carnitine challenge was observed in subjects with MetS compared with non-MetS. In MetS subjects (without CVD and T2D), gut microbiota composition was characterized by increased pro-inflammatory bacteria rather than TMAO-generating bacteria. The lack of statistical significance with regard to plasma TMAO response could be due to an insufficient sample size rather than the absence of an effect. Nevertheless, the observed elevation might still be clinically relevant, supported by concurrent differences in microbiota composition. These preliminary findings warrant validation in larger cohorts due to sample size limitations.

Background/Objectives: Trimethylamine N-oxide (TMAO) is a gut microbiota-dependent metabolite considered as a risk metabolite for various non-communicable diseases. This study aims to identify differences in the gut microbiota composition and concentrations of TMAO and related metabolites in subjects with and without metabolic syndrome (MetS).

Methods: Plasma samples were collected following an overnight fast on two occasions from subjects with (n = 12) and without (n = 21) MetS. Feces samples were collected on the day before the first blood sampling. The gut microbiota was profiled using 16S rRNA full-gene amplification sequencing. TMAO and related methylamines were quantified using UPLC-MSMS. The fasted plasma glucose, plasma lipid profile, and HbA1c were determined, and blood pressure, circumference, height, and weight were measured.

Results: A divergent gut microbiota composition was observed in feces samples from both groups. In contrast to subjects without MetS, subjects with MetS had a reduced microbial diversity, with lower Blautia glucerasea and higher Ruminococcus torques-a pattern associated with (increased) inflammation. Trimethylamine (TMA)-producing bacteria were low in abundance across both groups. While plasma TMAO and related methylamines displayed no significant differences between both groups, L-carnitine was elevated (p = 0.0191) in subjects with MetS. A strong positive correlation was detected between TMAO and TMA (r = 0.439, p = 0.003), with a tendency to correlate with carnitine (r = 0.212, p = 0.087).

Conclusions: Subjects with MetS were characterized by gut microbiota favoring inflammation-associated species but not TMA producers. This suggests that TMAO may not play a role in MetS subjects without overt comorbidities, e.g., CVD or T2D. The influence of the gut microbiota on early MetS is likely mediated through inflammatory mechanisms driven by specific bacterial shifts rather than TMAO production.

Polygenic scores (PGSs) for body mass index (BMI) may guide early prevention and targeted treatment of obesity. Using genetic data from up to 5.1 million people (4.6% African ancestry, 14.4% American ancestry, 8.4% East Asian ancestry, 71.1% European ancestry and 1.5% South Asian ancestry) from the GIANT consortium and 23andMe, Inc., we developed ancestry-specific and multi-ancestry PGSs. The multi-ancestry score explained 17.6% of BMI variation among UK Biobank participants of European ancestry. For other populations, this ranged from 16% in East Asian-Americans to 2.2% in rural Ugandans. In the ALSPAC study, children with higher PGSs showed accelerated BMI gain from age 2.5 years to adolescence, with earlier adiposity rebound. Adding the PGS to predictors available at birth nearly doubled explained variance for BMI from age 5 onward (for example, from 11% to 21% at age 8). Up to age 5, adding the PGS to early-life BMI improved prediction of BMI at age 18 (for example, from 22% to 35% at age 5). Higher PGSs were associated with greater adult weight gain. In intensive lifestyle intervention trials, individuals with higher PGSs lost modestly more weight in the first year (0.55 kg per s.d.) but were more likely to regain it. Overall, these data show that PGSs have the potential to improve obesity prediction, particularly when implemented early in life.

Prolonged use of antibacterial mouthwash is linked to an increased risk of systemic disease. We aimed to investigate if disturbing the oral microbiota would impact the lower gut microbiome with functional effects in diet-induced obesity. Mice were exposed to oral chlorhexidine and fed a Western diet (WD). Food intake and weight gain were monitored, and metabolic function, blood pressure, and microbiota were analyzed. Chlorhexidine reduced the number of viable bacteria in the mouth and lowered species richness in the gut but with proportional enrichment of some bacteria linked to metabolic pathways. In mice fed a Western diet, chlorhexidine reduced weight gain, body fat, steatosis, and plasma insulin without changing caloric intake, while increasing colon triglycerides and proteins, suggesting reduced absorption of these nutrients. The mechanisms behind these effects as well as the link between the oral microbiome and small intestinal function need to be pinpointed. While the short-term effects of chlorhexidine in this model appear beneficial, potential long-term disruptions in the oral and gut microbiota and possible malabsorption should be considered.