25-Hydroxyvitamin D status, light exposure and sleep quality in UK dwelling South Asian and Caucasian postmenopausal women

There is a lack of research into 25-hydroxyvitamin D (25(OH)D) status, light exposure and sleep patterns in South Asian populations. In addition, results of research studies are conflicting as to whether there is an association between 25(OH)D status and sleep quality. We investigated 25(OH)D status, self-reported and actigraphic sleep quality in n = 35 UK dwelling postmenopausal women (n = 13 South Asians, n = 22 Caucasians), who kept daily sleep diaries and wore wrist-worn actiwatch (AWL-L) devices for 14 days. A subset of n = 27 women (n = 11 South Asian and n = 16 Caucasian) also wore a neck-worn AWL-L device to measure their light exposure. For 25(OH)D concentration, South Asians had a median ± IQR of 43.8 ± 28.2 nmol/L, which was significantly lower than Caucasians (68.7 ± 37.4 nmol/L)(P = 0.001). Similarly, there was a higher sleep fragmentation in the South Asians (mean ± SD 36.9 ± 8.9) compared with the Caucasians (24.7 ± 7.1)(P = 0.002). Non-parametric circadian rhythm analysis of rest/activity patterns showed a higher night-time activity (L5) (22.6 ± 14.0 vs. 10.5 ± 4.4; P = 0.0008) and lower relative amplitude (0.85 ± 0.07 vs. 0.94 ± 0.02; P < 0.0001) in the South Asian compared with the Caucasian women. More South Asians (50%) met the criteria for sleep disorders (PSQI score >5) than did Caucasians (27%) (P = 0.001, Fishers Exact Test). However, there was no association between 25(OH)D concentration and any sleep parameter measured (P > 0.05) in either ethnic group. South Asians spent significantly less time in illuminance levels over 200 lx (P = 0.009) than did Caucasians. Overall, our results show that postmenopausal South Asian women have lower 25(OH)D concentration than Caucasian women. They also have higher sleep fragmentation, as well as a lower light exposure across the day. This may have detrimental implications for their general health and further research into sleep quality and light exposure in the South Asian ethnic group is warranted.

Vitamin D status and associated genetic polymorphisms in a cohort of UK children with non-alcoholic fatty liver disease

BACKGROUND

Vitamin D deficiency has been associated with non-alcoholic fatty liver disease (NAFLD). However, the role of polymorphisms determining vitamin D status remains unknown.

OBJECTIVES

The objectives of this study were to determine in UK children with biopsy-proven NAFLD (i) their vitamin D status throughout a 12-month period and (ii) interactions between key vitamin D-related genetic variants (nicotinamide adenine dinucleotide synthase-1/dehydrocholesterol reductase-7, vitamin D receptor, group-specific component, CYP2R1) and disease severity.

METHODS

In 103 paediatric patients with NAFLD, serum 25-hydroxyvitamin D (25OHD) levels and genotypes were determined contemporaneously to liver biopsy and examined in relation to NAFLD activity score and fibrosis stage.

RESULTS

Only 19.2% of children had adequate vitamin D status; most had mean 25OHD levels considered deficient (<25 nmol·L^-1 , 25.5%) or insufficient (<50 nmol·L^-1 , 55.3%). Patients had significantly lower 25OHD levels in winter months (95% CI: 22.7-31.2 nmol·L^-1 ) when compared with spring (30.5-42.1 nmol·L^-1 ; P = 0.0089), summer (36.3-47.2 nmol·L^-1 ; P < 0.0001) and autumn (34.2-47.5 nmol·L^-1 ; P = 0.0003). Polymorphisms in the nicotinamide adenine dinucleotide synthase-1/dehydrocholesterol reductase-7 (rs3829251, rs12785878) and vitamin D receptor (rs2228570) genes were independently associated with increased steatosis; while a group-specific component variant (rs4588) was associated with increased inflammation in liver biopsies.

CONCLUSIONS

Children with NAFLD in the UK have particularly low winter vitamin D status, with vitamin D insufficiency prevalent throughout the year. Polymorphisms in the vitamin D metabolic pathway are associated with histological severity of paediatric NAFLD.

Higher bone resorption excretion in South Asian women vs. White Caucasians and increased bone loss with higher seasonal cycling of vitamin D: Results from the D-FINES cohort study

Few data exist on bone turnover in South Asian women and it is not well elucidated as to whether Western dwelling South Asian women have different bone resorption levels to that of women from European ethnic backgrounds. This study assessed bone resorption levels in UK dwelling South Asian and Caucasian women as well as evaluating whether seasonal variation in 25-hydroxyvitamin D [25(OH)D] is associated with bone resorption in either ethnic group. Data for seasonal measures of urinary N-telopeptide of collagen (uNTX) and serum 25(OH)D were analysed from n=373 women (four groups; South Asian postmenopausal n=44, South Asian premenopausal n=50, Caucasian postmenopausal n=144, Caucasian premenopausal n=135) (mean (±SD) age 48 (14) years; age range 18-79years) who participated in the longitudinal D-FINES (Diet, Food Intake, Nutrition and Exposure to the Sun in Southern England) cohort study (2006-2007). A mixed between-within subjects ANOVA (n=192) showed a between subjects effect of the four groups (P<0.001) on uNTX concentration, but no significant main effect of season (P=0.163). Bonferroni adjusted Post hoc tests (P≤0.008) suggested that there was no significant difference between the postmenopausal Asian and premenopausal Asian groups. Season specific age-matched-pairs analyses showed that in winter (P=0.04) and spring (P=0.007), premenopausal Asian women had a 16 to 20nmolBCE/mmol Cr higher uNTX than premenopausal Caucasian women. The (amplitude/mesor) ratio (i.e. seasonal change) for 25(OH)D was predictive of uNTX, with estimate (SD)=0.213 (0.015) and 95% CI (0.182, 0.245; P<0.001) in a non-linear mixed model (n=154). This showed that individuals with a higher seasonal change in 25(OH)D, adjusted for overall 25(OH)D concentration, showed increased levels of uNTX. Although the effect size was smaller than for the amplitude/mesor ratio, the mesor for 25(OH)D concentration was also predictive of uNTX, with estimate (SD)=-0.035 (0.004), and 95% CI (-0.043, -0.028; P<0.001). This study demonstrates higher levels of uNTX in premenopausal South Asian women than would be expected for their age, being greater than same-age Caucasian women, and similar to postmenopausal Asian women. This highlights potentially higher than expected bone resorption levels in premenopausal South Asian women which, if not offset by concurrent increased bone formation, may have future clinical and public health implications which warrant further investigation. Individuals with a larger seasonal change in 25(OH)D concentration showed an increased bone resorption, an association which was larger than that of the 25(OH)D yearly average, suggesting it may be as important clinically to ensure a stable and steady 25(OH)D concentration, as well as one that is high enough to be optimal for bone health.

The effects of a diet rich in inulin or wheat fibre on markers of cardiovascular disease in overweight male subjects

BACKGROUND

Previous studies suggest that the beneficial health effects of a diet rich in whole grains could be a result of the individual fibres found in the grain. The present study aimed to investigate the influence of a diet high in either wheat fibre (as an example of an insoluble fibre) or inulin (a nondigestible carbohydrate) on markers of cardiovascular disease.

METHODS

Ten male participants classified as at higher risk of cardiovascular disease [mean (SD) body mass index 30.2 (3) kg m(-2) , mean (SD) waist circumference 106.4 (7) cm, mean (SD) age 39.8 (9) years] were recruited to a randomised, controlled, cross-over study comparing the consumption of bespoke bread rolls containing either inulin, wheat germ or refined grain (control) (15 g day(-1) ) for 4 weeks with a 4-week washout period between each regime. At the end of each regime, participants underwent an oral glucose tolerance test (OGTT), measures of pulse wave velocity (PWV), 24-h ambulatory blood pressure (AMBP), plasma lipid status and markers of glucose control.

RESULTS

There was no difference in measures of glucose control, lipid status, 24-h AMBP or PWV after the intervention periods and no changes compared to baseline. There was no significant difference between OGTT glucose and insulin time profiles; however, there was a significant difference in area under the curves between the wheat fibre and control interventions when comparing change from baseline (control +10.2%, inulin +4.3%, wheat fibre -2.5%; P = 0.03).

CONCLUSIONS

Only limited differences between the interventions were identified, perhaps as a consequence of the amount of fibre used and intervention length. The wheat germ intervention resulted in a significant reduction in glucose area under the curve, suggesting that this fibre may aid glucose control.

Greater seasonal cycling of 25-hydroxyvitamin D is associated with increased parathyroid hormone and bone resorption

SUMMARY

This analysis assessed whether seasonal change in 25-hydroxyvitamin D concentration was associated with bone resorption, as evidenced by serum parathyroid hormone and C-terminal telopeptide concentrations. The main finding was that increased seasonal fluctuation in 25-hydroxyvitamin D was associated with increased levels of parathyroid hormone and C-terminal telopeptide.

INTRODUCTION

It is established that adequate 25-hydroxyvitamin D (25(OH)D, vitamin D) concentration is required for healthy bone mineralisation. It is unknown whether seasonal fluctuations in 25(OH)D also impact on bone health. If large seasonal fluctuations in 25(OH)D were associated with increased bone resorption, this would suggest a detriment to bone health. Therefore, this analysis assessed whether there is an association between seasonal variation in 25(OH)D and bone resorption.

METHODS

The participants were (n = 279) Caucasian and (n = 88) South Asian women (mean (±SD); age 48.2 years (14.4)) who participated in the longitudinal Diet, Food Intake, Nutrition and Exposure to the Sun in Southern England study (2006-2007). The main outcomes were serum 25(OH)D, serum parathyroid hormone (sPTH) and serum C-terminal telopeptide of collagen (sCTX), sampled once per season for each participant.

RESULTS

Non-linear mixed modelling showed the (amplitude/mesor) ratio for seasonal change in log 25(OH)D to be predictive of log sPTH (estimate = 0.057, 95 % CI (0.051, 0.063), p < 0.0001). Therefore, individuals with a higher seasonal change in log 25(OH)D, adjusted for overall log 25(OH)D concentration, showed increased levels of log sPTH. There was a corresponding significant ability to predict the range of seasonal change in log 25(OH)D through the level of sCTX. Here, the corresponding parameter statistics were estimate = 0.528, 95 % CI (0.418, 0.638) and p ≤ 0.0001.

CONCLUSIONS

These findings suggest a possible detriment to bone health via increased levels of sPTH and sCTX in individuals with a larger seasonal change in 25(OH)D concentration. Further larger cohort studies are required to further investigate these preliminary findings.

Vitamin D deficiency in UK South Asian Women of childbearing age: a comparative longitudinal investigation with UK Caucasian women

SUMMARY

This is the first 1-year longitudinal study which assesses vitamin D deficiency in young UK-dwelling South Asian women. The findings are that vitamin D deficiency is extremely common in this group of women and that it persists all year around, representing a significant public health concern.

INTRODUCTION

There is a lack of longitudinal data assessing seasonal variation in vitamin D status in young South Asian women living in northern latitudes. Studies of postmenopausal South Asian women suggest a lack of seasonal change in 25-hydroxy vitamin D [25(OH)D], although it is unclear whether this is prevalent among premenopausal South Asians. We aimed to evaluate, longitudinally, seasonal changes in 25(OH)D and prevalence of vitamin D deficiency in young UK-dwelling South Asian women as compared with Caucasians. We also aimed to establish the relative contributions of dietary vitamin D and sun exposure in explaining serum 25(OH)D.

METHODS

This is a 1-year prospective cohort study assessing South Asian (n = 35) and Caucasian (n = 105) premenopausal women living in Surrey, UK (51° N), aged 20-55 years. The main outcome measured was serum 25(OH)D concentration. Secondary outcomes were serum parathyroid hormone, self-reported dietary vitamin D intake and UVB exposure by personal dosimetry.

RESULTS

Serum 25(OH)D <25 nmol/L was highly prevalent in South Asians in the winter (81 %) and autumn (79.2 %). Deficient status (below 50 nmol/L) was common in Caucasian women. Multi-level modelling suggested that, in comparison to sun exposure (1.59, 95 %CI = 0.83-2.35), dietary intake of vitamin D had no impact on 25(OH)D levels (-0.08, 95 %CI = -1.39 to 1.23).

CONCLUSIONS

Year-round vitamin D deficiency was extremely common in South Asian women. These findings pose great health threats regarding the adverse effects of vitamin D deficiency in pregnancy and warrant urgent vitamin D public health policy and action.

Promoting healthy diet and exercise patterns amongst primary school children: a qualitative investigation of parental perspectives

Parents represent a potentially powerful intermediary in behaviour change strategies aimed at improving the lifestyle behaviours of young children. However, to fulfil this role, parents need to have the necessary knowledge and motivation to assimilate dietary guidelines. This study aimed to assess these psychosocial constructs, and subsequent parental receptiveness to nutrition education, through investigation of the barriers and benefits perceived by parents to the provision of a healthy diet and adequate exercise for their children. A qualitative methodology was employed and 41 parents took part in seven focus groups separated by socio-economic status (SES). Across the groups, a combination of reported external barriers and unconscious internal barriers, stemming from high optimistic bias, low perceived control and unrealistic health expectations, were observed. SES differences were suggested in restrictive feeding practices, the responsibility attributed to the school and in the level and format of desired nutrition education. Overall a demand for interventions focusing on behavioural techniques rather than fact transmission was uncovered, in particular the promotion of parental self-awareness to reduce negative influences within the family food environment. Providing realistic definitions of appropriate behaviour and empowering parents to tackle children's weight issues were indicated as important targets for future education programmes.

An investigation into school children's knowledge and awareness of food and nutrition

With the diet and exercise behaviours of UK school children showing little improvement over recent years, the need for dietary change is clearly indicated. This study aimed to assess the nutritional knowledge and understanding of primary school children in order to identify the most effective format for future nutrition messages. A qualitative methodology was employed and 114 children, aged 7-11 years, took part in 23 focus groups separated by age, gender and socio-economic status (SES). Issues discussed included parental food rules, children's perceptions of 'good' and 'bad' foods, diet-disease links and food groupings. Across the groups restrictive food rules were most frequently reported whilst between groups gender and SES differences were apparent in relation to parental control over food and children's nutritional knowledge. The limitations of the children's cognitive development could be seen in their conceptualization of food groups, where concrete grouping schemes were frequently used, and in the lack of understanding inherent in their food-health or food-nutrient associations. Taste and preference were confirmed as consistent influences in children's food classification. Primary school children may be receptive to food based dietary guidelines based on familiar, concrete food classifications. These should be cognitively appropriate and possibly need to be gender specific.

Clinical strategies for improving the radiotherapeutic management of prostate cancer

The goal of treatment of localized and locally advanced prostate cancer is to cure without causing unacceptable complications. The recognition that cure rates for localized and locally advanced prostate cancer treated with traditional means are far lower than previously estimated (1-4) has provided the impetus to seek improved local therapies. In particular, 3D conformal radiation therapy (3D-CRT) and the combination of radiation and hormone therapy are promising. Advances in these and other areas are discussed below.