Anaemia is a global public health problem affecting women worldwide, and reproductive-age women are at increased risk. We conducted a population-based cross-sectional study analysing the prevalence of overall anaemia and anaemia according to severity in Chinese pre-pregnant women to update current knowledge on anaemia epidemiology. Based on the National Free Preconception Check-up Projects supported by the Chinese government, 5 679 782 women participating in this project in 2017 were included in the present study. The cyanmethemoglobin method was applied to assess Hb concentrations. Univariate and multivariate logistic regressions were applied for associated factors. The prevalence of anaemia among Chinese pre-pregnant women was 21·64 % (mild: 14·10 %, moderate: 7·17 % and severe : 0·37 %). The prevalence of overall and severe anaemia was the highest in Tibet and the lowest in Beijing among thirty-one provinces. Women’s age, region, ethnic origin, educational level, occupation and pregnancy history were all correlated with anaemia. Women with B blood type (adjusted OR (aOR) = 0·89), higher BMI (overweight: aOR = 0·84; obesity: aOR = 0·70) and alcohol consumption (aOR = 0·69) were less likely to have anaemia, while those with rhesus negative blood type (aOR = 1·10), history of anaemia (aOR = 2·60), older age at menarche (aOR = 1·19), heavy menstrual blood loss (aOR = 1·39), longer menstrual period (aOR = 1·09) and shorter menstrual cycle (aOR = 1·08) were more likely to suffer from anaemia. Meat or egg eaters were not significantly associated with severe anaemia. Anaemia is of moderate public health significance among Chinese pre-pregnant women. Interventions should be considered to prevent anaemia to the greatest extent possible to avoid potential harm in this population.

Sleep hygiene recommendations discourage eating before bedtime; however, the impact of mealtime on sleep has been inconsistent. We examined gender-stratified associations between eating or drinking <1, <2 and <3 h before bedtime, sleep duration and wake after sleep onset (WASO >30 min). This study utilised 2003–2018 data from the American Time Use Survey, a nationally representative sample of USA residents aged ≥15 years. Participants recorded weekday/weekend activities during a 24-h period. Age-specific sleep duration and WASO were estimated categorically and continuously. Eating or drinking were identified from all activities recorded <1, <2 and <3 h before bedtime. Mean ± se sleep duration was 8·0 ± 0·006 h, and 6% of participants ate or drank <1 h prior to weekdays bedtime. Overall, eating or drinking <1 h prior to bedtime was associated with longer weekdays sleep duration. Women and men who ate or drank <1 h before bedtime, v. those who did not, had 35 min (95% CI (30,39)) and 25 min (95 % CI (21,29)) longer sleep duration, respectively, as well as increased odds of WASO; women (OR=2·03, 95% CI (1·66,2·49)) and men (OR=2·64, 95% CI (2·08,3·36)). As the interval of eating or drinking prior to bedtime expanded, odds of short and long sleep durations and WASO decreased. This population-based data linked eating or drinking <1 h before bedtime to longer sleep duration, but increased WASO. Eating or drinking further from bedtime lowers the odds of short and long sleep duration and WASO. Causal pathways are difficult to discern, though inefficient sleep after late-night eating could increase WASO and trigger compensatory increases in sleep duration.

There is limited data on the dietary patterns of 5-year-old children in Asia. The study examined childhood dietary patterns and their maternal and child correlates in a multi-ethnic Asian cohort. Based on caregiver-reported 1-month quantitative FFQ of 777 children from the Growing Up in Singapore Towards healthy Outcomes cohort, cluster analysis identified two mutually exclusive clusters. Children in the ‘Unhealthy’ cluster (43·9 %) consumed more fries, processed meat, biscuits and ice cream, and less fish, fruits and vegetables compared with those in the ‘Healthy’ cluster (56·1 %). Children with mothers of lower educational attainment had twice the odds of being assigned to the ‘Unhealthy’ cluster (adjusted OR (95 % CI) = 2·19 (95 % CI 1·49–3·24)). Children of Malay and Indian ethnicities had higher odds of being assigned to the ‘Unhealthy’ cluster (adjusted OR = 25·46 (95 % CI 15·40, 42·10) and 4·03 (95 % CI 2·68–6·06), respectively), relative to Chinese ethnicity. In conclusion, this study identified two dietary patterns in children, labelled as the ‘Unhealthy’ and ‘Healthy’ clusters. Mothers’ educational attainment and ethnicity were two correlates that were associated with the children’s assignments to the clusters. These findings can assist in informing health promotion programmes targeted at Asian children.

We aimed to evaluate the association between eating context patterns and ultraprocessed food consumption at two main meal occasions in a representative sample of UK adolescents. Data were acquired from 4-d food records of adolescents aged 11–18 years, who participated in the 2014–2016 UK National Diet and Nutrition Survey (n 542). The eating context was assessed considering the location of the meal (lunch and dinner) occasion, the individuals present, whether the television was on and if the food was consumed at a table. Ultraprocessed foods were identified using the NOVA classification. Exploratory factor analysis was used to identify eating context patterns for lunch and dinner. Linear regression models adjusted for the covariates were utilised to test the association between eating context patterns and the proportion of total daily energy intake derived from ultraprocessed foods. Their contribution was about 67 % to energy intake. Three patterns were retained for lunch (‘At school with friends’, ‘TV during family meal’ and ‘Out-of-home (no school)’), and three patterns were retained for dinner (‘Watching TV alone in the bedroom’, ‘TV during family meal’ and ‘Out-of-home with friends’). At lunch, there was no significant association between any of the three patterns and ultraprocessed food consumption. At dinner, the patterns ‘Watching TV alone in the bedroom’ (coefficient: 4·95; 95 % CI 1·87, 8·03) and ‘Out-of-home with friends’ (coefficient: 3·13; 95 % CI 0·21, 6·14) were associated with higher consumption of ultraprocessed food. Our findings suggest a potential relationship between the immediate eating context and ultraprocessed food consumption by UK adolescents.

Advice on replacing unhealthy foods with healthier alternatives within the same food category may be more acceptable and might ease the transition towards a healthy diet. Here, we studied the potential impact of substitutions within the pizza category on the risk of type 2 diabetes (T2D). The study sample consisted of 2510 adults from the INCA2 French national survey. Based on their nutritional characteristics, the 353 pizzas marketed in France were grouped into 100 clusters that were used to run various scenarios of pizza substitutions, which were either isoenergetic (IE) or non-isoenergetic (NIE). We then used a model structurally similar to the Preventable Risk Integrated ModEl to assess the expected rate of change in risk of T2D. Pizzas characterised by a low energy, high vegetable content and whole grain dough were associated with a greater reduction in the risk of T2D. The rates of change in risk of T2D were markedly stronger in men and for NIE substitutions. When the rates of change were estimated in the subsample of pizza consumers, replacing the observed pizzas with the best pizza resulted in a T2D risk reduction of −6·7 % (–8·4 %; −4·9 %, IE) and −8·9 % (–11·2 %; −6·3 %, NIE), assuming that this is their usual diets. The greatest risk reduction induced by an IE substitution of the observed pizza with a mixed dish was similar to that observed with the best pizzas. Overall, this modelling study suggests that healthy swaps within a category can effectively supplement broader dietary changes towards a healthier diet.

Breast cancer prevention is of great importance to reduce high incidence in South Africa. This study aimed to investigate adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Cancer Prevention Recommendations and the association with breast cancer risk in black urban women from Soweto, South Africa. A total of 396 breast cancer cases and 396 population-based controls from the South African Breast Cancer study (SABC) matched on age and demographic settings were included. Validated questionnaires were used to collect dietary and epidemiological data. To assess adherence to these recommendations, an eight-point adherence score was developed, using tertiles among controls for scoring each recommendation (0, 0·5 and 1) with zero indicating the lowest adherence to the recommendations. OR and 95 % CI were estimated using multivariate logistic regression models to analyse associations between the WCRF/AICR score and breast cancer risk. Greater adherence (>4·5 v. <3·25) to the 2018 WCRF/AICR Cancer Prevention Recommendations was associated with a significant inverse association with breast cancer risk overall (OR = 0·54, 95 % CI 0·35, 0·91) and specifically in postmenopausal women (OR = 0·55, 95 % CI 0·34, 0·95), in cases with oestrogen positive and progesterone positive breast cancer subtypes (OR = 0·54, 95 % CI 0·39, 0·89 and OR = 0·68, 95 % CI 0·43, 0·89, respectively) and in obese women (OR = 0·52, 95 % CI 0·35, 0·81). No significant association with breast cancer risk was observed in premenopausal women. Greater adherence to the 2018 WCRF/AICR Cancer Prevention Recommendations may reduce breast cancer risk in this black urban population of Soweto. Adherence thereof should be encouraged and form a part of cost-effective breast cancer prevention guidelines.

Only a few studies have investigated the association between psychological stress and the healthfulness of plant-based diets while accounting for variances in age groups and regions. In light of this, this study aimed to identify the food groups that contribute the most to the relationship between the healthfulness of plant-based diets and psychological stress in female students in Saudi Arabia. This cross-sectional study, which included 401 female college students aged 19–35 years, collected data on blood, anthropometric indices, the perceived stress scale-10 (PSS-10) and diet using the Saudi food frequency questionnaire. An overall plant-based diet index (PDI), healthy PDI, and an unhealthy PDI (uPDI) were defined. Multiple linear regression analyses were applied to examine the associations between PSS-10 and PDI and hPDI and uPDI. No associations between the PSS-10 score and the overall PDI or uPDI scores were found; however, a six-point higher hPDI score was associated with a 0·16-point lower PSS-10 score (95 % CI, –0·24, –0·08) after controlling for lifestyle factors. Moreover, adjustments for healthy food groups, including vegetables and fruits, attenuated the association between the hPDI and PSS-10. In conclusion, healthy plant-based diets are associated with lower psychological stress in young Saudi women. This finding highlights the importance, especially for female students, of following diets that are not only plant-based but are also healthy and rich in fruits and vegetables.

A daily intake of dairy products is recommended in many countries in order to maintain optimal health throughout life. However, evidence regarding the association between intake of individual dairy products and mortality is limited. We therfore, explored associations between intake of different dairy products and all-cause and cause-specific mortality using specified theoretical substitution analyses. We analysed data from 55 775 Danish men and women aged 50–64 years between 1993 and 1997. Information about dairy product intake at baseline was collected using a validated food frequency questionnaire. Information about vital status and causes of death was obtained through national registers. Measures of associations were calculated using Cox proportional hazards regression. During a median follow-up of 19·0 years, 11 586 participants died. For all-cause mortality, we observed that the intake of low-fat milk, whole-fat milk or low-fat yogurt products in place of cheese was associated with a higher rate of death (hazard ratios between 1·03 and 1·12 per serving/d substituted). The same pattern was present for CVD mortality. For cancer mortality, whole-fat milk and low-fat yogurt products in place of cheese were also associated with a higher rate of death for men while for women, whole-fat milk in place of buttermilk was associated with a higher cancer mortality rate. The results appeared robust in several sensitivity analyses. Our results suggest that intake of low-fat milk, whole-fat milk or low-fat yogurt products in place of cheese is associated with a higher rate of all-cause and cause-specific mortality.

The association between a dietary pattern characterised by high alcohol intake and dyslipidaemia has not been fully investigated. Therefore, the present study aimed to investigate the association between alcohol dietary patterns and the prevalence of dyslipidaemia and its components. This cross-sectional study enrolled 2171 men and women aged ≥40 years who were alumni of a Japanese university. To identify dietary patterns, a principal component analysis was performed based on the energy-adjusted food intake estimated by a brief-type self-administered diet history questionnaire. Three dietary patterns were identified, the second of which was named the alcohol dietary pattern and was characterised by a high intake of alcoholic beverages, liver, chicken and fish. This alcohol dietary pattern was associated with reduced LDL-cholesterol levels. The fully adjusted OR (95 % CI) of high LDL-cholesterol for the lowest through highest quartile of alcohol dietary pattern score were 1·00 (reference), 0·83 (0·64, 1·08), 0·84 (0·64, 1·10) and 0·68 (0·49, 0·94), respectively. Subgroup analysis showed that the alcohol dietary pattern was inversely associated with the prevalence of dyslipidaemia in women, whereas it was positively associated with high TAG levels in men. In conclusion, the alcohol dietary pattern, characterised by a high intake of alcoholic beverages, liver, chicken and fish, was associated with the prevalence of dyslipidaemia and its components. This finding provides useful information for the prevention and treatment of dyslipidaemia by modifying the diet.

Numerous studies have revealed strong relationships between COVID-19 and inflammation. However, the imminent link between diet-related inflammation and the COVID-19 risk has not been addressed before. So, we explored the capability of the Energy-Adjusted Dietary Inflammatory Index (E-DII) to predict the inflammatory markers, incidence and severity of COVID-19. We conducted a case-control study consisting of 120 adults; they had been admitted for COVID-19 at hospital during June and July, 2020. The E-DII score was calculated based on the dietary intake, which was evaluated by a 138-item semi-quantitative food frequency questionnaire. Serum levels of inflammatory markers including the Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and White blood cells (WBCs) differential were measured. Severity of disease was assessed by chest radiology criteria. Patients with the maximum pro-inflammatory energy adjusted E-DII score had 7·26 times greater odds of developing COVID-19, as compared to those in tertiles 1 (E-DII T3v. E-DII T1: OR = 7·26; 95 % CI 2·64 to 9·94, P < 0·001). Also, a positive association between E-DII and C-reactive protein (CRP) was observed (BE-DII = 1·37, 95 % CI 0·72, 2·02), such that with each unit increase in E-E-DII, the CRP levels were increased by 1·37 units. Furthermore, a significant association was found between E-DII and the severity of disease (BE-DII = 0·03, 95 % CI 0·01, 0·06. 0·024). Patients consuming a diet with a higher pro-inflammatory potential were at a greater risk of COVID-19 occurrence; also, the severity of disease was elevated with a high score inflammatory diet.

Obesity remains a serious relevant public health concern throughout the world despite related countermeasures being well understood (i.e. mainly physical activity and an adjusted diet). Among different nutritional approaches, there is a growing interest in ketogenic diets (KD) to manipulate body mass (BM) and to enhance fat mass loss. KD reduce the daily amount of carbohydrate intake drastically. This results in increased fatty acid utilisation, leading to an increase in blood ketone bodies (acetoacetate, 3-β-hydroxybutyrate and acetone) and therefore metabolic ketosis. For many years, nutritional intervention studies have focused on reducing dietary fat with little or conflicting positive results over the long term. Moreover, current nutritional guidelines for athletes propose carbohydrate-based diets to augment muscular adaptations. This review discusses the physiological basis of KD and their effects on BM reduction and body composition improvements in sedentary individuals combined with different types of exercise (resistance training or endurance training) in individuals with obesity and athletes. Ultimately, we discuss the strengths and the weaknesses of these nutritional interventions together with precautionary measures that should be observed in both individuals with obesity and athletic populations. A literature search from 1921 to April 2021 using Medline, Google Scholar, PubMed, Web of Science, Scopus and Sportdiscus Databases was used to identify relevant studies. In summary, based on the current evidence, KD are an efficient method to reduce BM and body fat in both individuals with obesity and athletes. However, these positive impacts are mainly because of the appetite suppressive effects of KD, which can decrease daily energy intake. Therefore, KD do not have any superior benefits to non-KD in BM and body fat loss in individuals with obesity and athletic populations in an isoenergetic situation. In sedentary individuals with obesity, it seems that fat-free mass (FFM) changes appear to be as great, if not greater, than decreases following a low-fat diet. In terms of lean mass, it seems that following a KD can cause FFM loss in resistance-trained individuals. In contrast, the FFM-preserving effects of KD are more efficient in endurance-trained compared with resistance-trained individuals.

Polycystic ovary syndrome (PCOS) is associated with a higher prevalence of sleep disturbances and obesity. Treatment of PCOS includes modifying lifestyle behaviours associated with weight management. However, poor sleep in the non-PCOS population has been associated with poorer lifestyle behaviours. The aim was to investigate whether sleep disturbance confounds or modifies the association between lifestyle factors and PCOS. This was a cross-sectional analysis from the Australian Longitudinal Study on Women’s Health cohort aged 31–36 years in 2009 were analysed (n 6067, 464 PCOS, 5603 non-PCOS). Self-reported data were collected on PCOS, anthropometry, validated modified version of the Active Australia Physical Activity survey, validated FFQ and sleep disturbances through latent class analysis. Women with PCOS had greater adverse sleep symptoms including severe tiredness (P = 0·001), difficulty sleeping (P < 0·001) and restless sleep (P < 0·001), compared with women without PCOS. Women with PCOS also had higher energy consumption (6911 (sd 2453) v. 6654 (sd 2215) kJ, P = 0·017), fibre intake (19·8 (sd 7·8) v. 18·9 (sd 6·9) g, P = 0·012) and diet quality (dietary guidelines index (DGI)) (88·1 (sd 11·6) v. 86·7 (sd 11·1), P = 0·008), lower glycaemic index (50·2 (sd 4·0) v. 50·7 (sd 3·9), P = 0·021) and increased sedentary behaviour (6·3 (sd 2·8) v. 5·9 (sd 2·8) h, P = 0·009). There was a significant interaction between PCOS and sleep disturbances for DGI (P = 0·035), therefore only for women who had adequate sleep was PCOS associated with a higher DGI. For women with poorer sleep, there was no association between PCOS and DGI. The association between PCOS and improved diet quality may only be maintained if women can obtain enough good quality sleep.

Healthy Nordic diet has been beneficially associated with CHD risk factors, but few studies have investigated risk of developing CHD. We investigated the associations of healthy Nordic diet with major CHD risk factors, carotid atherosclerosis and incident CHD in middle-aged and older men from eastern Finland. A total of 1981 men aged 42–60 years and free of CHD at baseline in 1984–1989 were investigated. Diet was assessed with 4-d food recording and the healthy Nordic diet score was calculated based on the Baltic Sea Diet Score. Carotid atherosclerosis was assessed by ultrasonography of the common carotid artery intima–media thickness in 1053 men. ANCOVA and Cox proportional hazards regression analyses were used for analyses. Healthy Nordic diet score was associated with lower serum C-reactive protein (CRP) concentrations (multivariable-adjusted extreme-quartile difference 0·66 mg/l, 95 % CI 0·11, 1·21 mg/l) but not with serum lipid concentrations, blood pressure or carotid atherosclerosis. During the average follow-up of 21·6 years (sd 8·3 years), 407 men had a CHD event, of which 277 were fatal. The multivariable-adjusted hazard ratios in the lowest v. the highest quartile of the healthy Nordic diet score were 1·15 (95 % CI 0·87, 1·51) for any CHD event (P trend 0·361) and 1·44 (95 % CI 0·99, 2·08) (P trend 0·087) for fatal CHD event. We did not find evidence that adherence to a healthy Nordic diet would be associated with a lower risk of CHD or with carotid atherosclerosis or major CHD risk factors, except for an inverse association with serum CRP concentrations.

Using data from a nationally generalisable birth cohort, we aimed to: (i) describe the cohort’s adherence to national evidence-based dietary guidelines using an Infant Feeding Index (IFI) and (ii) assess the IFI’s convergent construct validity, by exploring associations with antenatal maternal socio-demographic and health behaviours and with child overweight/obesity and central adiposity at age 54 months. Data were from the Growing Up in New Zealand cohort (n 6343). The IFI scores ranged from zero to twelve points, with twelve representing full adherence to the guidelines. Overweight/obesity was defined by BMI-for-age (based on the WHO Growth Standards). Central adiposity was defined as waist-to-height ratio > 90th percentile. Associations were tested using multiple linear regression and Poisson regression with robust variance (risk ratios, 95 % CI). Mean IFI score was 8·2 (sd 2·1). Maternal characteristics explained 29·1 % of variation in the IFI score. Maternal age, education and smoking had the strongest independent relationships with IFI scores. Compared with children in the highest IFI tertile, girls in the lowest and middle tertiles were more likely to be overweight/obese (1·46, 1·03, 2·06 and 1·56, 1·09, 2·23, respectively) and boys in the lowest tertile were more likely to have central adiposity (1·53, 1·02, 2·30) at age 54 months. Most infants fell short of meeting national Infant Feeding Guidelines. The associations between IFI score and maternal characteristics, and children’s overweight/obesity/central adiposity, were in the expected directions and confirm the IFI’s convergent construct validity.

The association between fruit and vegetable consumption before and during pregnancy and offspring’s physical growth has been well reported, but no study has focused on offspring’s neurological development. We aimed to explore the association between maternal fruit and vegetable consumption before and during pregnancy and developmental delays in their offspring aged 2 years. Between July 2013 and March 2017, 23 406 women were recruited for the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Fruit and vegetable consumption was calculated using FFQ, and offspring’s developmental delays were evaluated by the Ages & Stages Questionnaires, Third Edition (ASQ-3) for infants aged 2 years. Finally, 10 420 women and 10 543 infants were included in the analysis. Totally, 14·9 % of children had developmental delay when screened using the ASQ-3. Women in the highest quartile of vegetable consumption from pre-pregnancy to early pregnancy and from early to mid-pregnancy had lower odds of offspring’s developmental delays (OR 0·74; 95 % CI 0·63, 0·89 and OR 0·70; 95 % CI 0·59, 0·84, respectively) than women in the lowest quartile. Women in the highest quartile of fruit consumption from early to mid-pregnancy had lower odds of offspring’s developmental delays (OR 0·78; 95 % CI 0·66, 0·92) than women in the lowest quartile. In conclusion, high fruit and vegetable consumption before and during pregnancy was associated with a lower risk of developmental delays in offspring aged 2 years.

We assessed longitudinal association between calcium intake during adolescence and hypertension in adulthood. Longitudinal study data of 1611 participants from the China Health and Nutrition Survey during 1991–2011 were used. On average they were followed for 11·4 years. Dietary calcium intake during adolescence was assessed based on three 24-hour dietary recalls collected in each visit/survey between 1991 and 2009 (seven waves). The intake was recoded into quartiles. Cumulative mean±SD calcium intake was 199·9±144·8 mg/1000 kcal/day during adolescence. In total 102 participants had hypertension in adulthood (97 men and 5 women). There was a clear U-shaped association between adolescence calcium intake quartiles and adulthood hypertension: across the quartiles, hypertension prevalence was 6·7%, 4·0%, 5·2% and 9·5%, respectively. After adjustment for potential confounders including weight status and dietary pattern, odds ratios (OR, 95% CI) for hypertension were 2·32 (95% CI 1·07–5·00) for lowest quartile, 1·00 (reference), 1·34 (95% CI 0·61–2·97), and 3·10 (95% CI 1·49–6·46) across the quartiles. Lower or higher calcium intake during adolescence was associated with hypertension in adulthood independent of weight status and dietary pattern.

Current cancer prevention recommendations advise limiting red meat intake to <500 g/week and avoiding consumption of processed meat, but do not differentiate the source of processed meat. We examined the associations of processed meat derived from red v. non-red meats with cancer risk in a prospective cohort of 26 218 adults who reported dietary intake using the Canadian Diet History Questionnaire. Incidence of cancer was obtained through data linkage with Alberta Cancer Registry with median follow-up of 13·3 (interquartile range (IQR) 5·1) years. Multivariable Cox proportional hazards regression models were adjusted for covariates and stratified by age and sex. The median consumption (g/week) of red meat, processed meat from red meat and processed meat from non-red meat was 267·9 (IQR 269·9), 53·6 (IQR 83·3) and 11·9 (IQR 31·8), respectively. High intakes (4th Quartile) of processed meat from red meat were associated with increased risk of gastrointestinal cancer adjusted hazard ratio (AHR): 1·68 (95 % CI 1·09, 2·57) and colorectal cancers AHR: 1·90 (95 % CI 1·12, 3·22), respectively, in women. No statistically significant associations were observed for intakes of red meat or processed meat from non-red meat. Results suggest that the carcinogenic effect associated with processed meat intake may be limited to processed meat derived from red meats. The findings provide preliminary evidence towards refining cancer prevention recommendations for red and processed meat intake.