Arterial Stiffness and Incident Glaucoma: A Large Population-Based Cohort Study.

PURPOSE: To investigate whether arterial stiffness, assessed oscillometrically, is associated with incident glaucoma in the Vitamin D Assessment (ViDA) Study cohort, aged 50 to 84 years. DESIGN: Prospective, population-based cohort study. METHODS: Arterial stiffness was assessed in 4,713 participants without known glaucoma (mean ± SD age = 66 ± 8 years) from 5 April 2011 to 6 November 2012 by way of aortic PWV (aPWV), estimated carotid-femoral PWV (ePWV) and aortic PP (aPP). Incident glaucoma was identified through linkage to national prescription and hospital discharge registers. Relative risks of glaucoma for each arterial stiffness measure were estimated by Cox proportional hazards regression, over the continuum of values and by quartiles. RESULTS: During a mean ± SD follow-up of 10.5±0.4 years, 301 participants developed glaucoma. Arterial stiffness, as measured by aPWV (Hazard ratio (HR) per SD increase, 1.36, 95% CI 1.14-1.62) and ePWV (HR per SD increase, 1.40, 95% CI 1.14-1.71) but not aPP (HR per SD increase, 1.06, 95% CI 0.92-1.23) was associated with incident glaucoma. When arterial stiffness was analyzed as a categorical variable, the highest quartiles of aPWV (HR, 2.62, 95% CI 1.52-4.52; Ptrend = .007), ePWV (HR, 2.42, 95%CI 1.37-4.27; Ptrend = .03), and aPP (HR, 1.68, 95%CI 1.10-2.5; Ptrend = .02) were associated with the development of glaucoma. CONCLUSIONS: Arterial stiffness measured with a simple oscillometric device predicted the development of glaucoma and could potentially be used in clinical practice to help identify people at risk of this condition. It may also present a new therapeutic research avenue, including in respect of systemic antihypertensives.

Increased risk of cardiovascular and renal disease, and diabetes for all women diagnosed with gestational diabetes mellitus in New Zealand-A national retrospective cohort study.

BACKGROUND: Gestational diabetes mellitus increases the risk of developing type 2 diabetes. The aim of this study is to compare cardiometabolic and renal outcomes for all women in New Zealand with gestational diabetes (2001-2010) with women without diabetes, 10-20 years following delivery. METHODS: A retrospective cohort study, utilizing a national dataset providing information for all women who gave birth between 1 January 2001 and 31 December 2010 (n = 604 398). Adolescent girls <15 years, women ≥50 years and women with prepregnancy diabetes were excluded. In total 11 459 women were diagnosed with gestational diabetes and 11 447 were matched (for age and year of delivery) with 57 235 unexposed (control) women. A national hospital dataset was used to compare primary outcomes until 31 May 2021. RESULTS: After controlling for ethnicity, women with gestational diabetes were significantly more likely than control women to develop diabetes-adjusted hazard ratio (HR) 20.06 and 95% confidence interval (CI) 18.46-21.79; a first cardiovascular event 2.19 (1.86-2.58); renal disease 6.34 (5.35-7.51) and all-cause mortality 1.55 (1.31-1.83), all p values <.0001. The HR and 95% CI remained similar after controlling for significant covariates: diabetes 18.89 (17.36-20.56), cardiovascular events 1.79 (1.52-2.12), renal disease 5.42 (4.55-6.45), and all-cause mortality 1.44 (1.21-1.70). When time-dependent diabetes was added to the model, significance remained for cardiovascular events 1.33 (1.10-1.61), p = .003 and renal disease 2.33 (1.88-2.88), p < .0001 but not all-cause mortality. CONCLUSIONS: Women diagnosed with gestational diabetes have an increased risk of adverse cardiometabolic and renal outcomes. Findings highlight the importance of follow-up screening for diabetes, cardiovascular risk factors, and renal disease.

A prediction tool for vitamin D deficiency in New Zealand adults.

PURPOSE: This study aims to develop a model for predicting vitamin D deficiency in New Zealand adults using easily accessible clinical characteristics. METHODS: Data were derived from the Vitamin D Assessment (ViDA) study dataset. Included participants in the main analysis were aged 50-84 years and resided in Auckland, New Zealand. The dataset was split into a discovery dataset in which the prediction model was developed (n = 2036) and a validation dataset in which it was tested (n = 2037). The prediction model was developed using clinical characteristics in a logistic regression analysis with deseasonalised serum 25OHD (DS-25OHD) as the dependent variable. RESULTS: DS-25OHD < 40 nmol/L was found in 8.2% of European participants, 18.8% of Maori participants, 23.1% of Pacific participants and 52.2% of South Asian participants. Predictors for DS-25OHD < 40 nmol/L in the European sub-cohort included increasing age, female sex, higher body mass index, current smoking, no alcohol intake, lower self-reported general health status, lower physical activity hours, lower outdoor hours and no use of vitamin D-containing supplementation. The area under the curve in the discovery dataset was 0.73, and in the validation dataset was 0.71. Of those with a prediction score ≥ 10 (total risk score range 0-21.5), the sensitivity and specificity for predicting vitamin D deficiency was 0.90 and 0.41, respectively. CONCLUSION: Non-European ethnicity is an important risk factor for vitamin D deficiency. Our vitamin D deficiency prediction model performed well and demonstrates its potential as a tool that can be integrated into clinical practice for the prediction of vitamin D deficiency.

Ten-second central SBP variability predicts first and recurrent cardiovascular events.

OBJECTIVE: Long-term (day-to-day or visit-to-visit) blood pressure variability (BPV) predicts elevated risk of cardiovascular events but represents just one BPV type. We examined whether 10-s BPV predicts cardiovascular events. METHODS: In 4999 adults (58% men; aged 50-84 years; 670 with a prior cardiovascular event), we performed suprasystolic brachial pressure measurements over ∼10 s, yielding aortic pressure waveforms. BPV was calculated by average real variability (ARV), root mean square of successive differences, standard deviation (SD), coefficient of variation and relative range. Participants were followed up for 4.6 years (median), accruing 310 first and 187 recurrent cardiovascular events, respectively. RESULTS: In multivariable-adjusted analyses, all central SBPV parameters were associated with first cardiovascular events: the standardized hazard ratio for each ranged from 1.25 to 1.29. The hazard ratio between the lowest and highest sextile ranged from 1.92 [95% confidence interval (CI) 1.31-2.80] for coefficient of variation to 2.19 (95% CI 1.38-3.46) for ARV. All central SBPV parameters also were associated with higher risk of recurrent cardiovascular events: adjusted standardized hazard ratio ranged from 1.16 to 1.21. Because of fewer recurrent events, these low-versus-high comparisons were based on tertiles; hazard ratios between the lowest and highest tertiles ranged from 1.50 (95% CI 1.02-2.23) for ARV to 1.76 (95% CI 1.20-2.60) for SD. The highest categorical net reclassification improvement for 5-year risk of first cardiovascular events was 13% (95% CI 7-18%) and substantially higher among those with intermediate (10-20%) risk: 39% (95% CI 26-52%). CONCLUSION: Ten-second central SBPV parameters predict first and recurrent cardiovascular events.

Pulse rate variability predicts atrial fibrillation and cerebrovascular events in a large, population-based cohort.

BACKGROUND: Many patients with atrial fibrillation (AF) present with stroke as their first clinical manifestation and since improved AF screening methods are thus required, we investigated whether pulse rate variability parameters predict future AF and cerebrovascular events. METHODS: In an observational cohort study of 5000 community-resident adults (58% male; 50-84 years), the beat-to-beat variability of suprasystolic brachial blood pressure waveforms was measured with root mean square of successive differences (RMSSD) and irregularity index (IrrIx). Based on outcome-oriented and previously validated thresholds for detecting AF, RMSSD and IrrIx were dichotomised at 100 ms and 7.7%, respectively. Participants were followed up for 4.6 years (median), accruing 249 AF and 120 cerebrovascular events in the total sample (n = 5000), and 133 AF and 90 cerebrovascular events among those without prior AF diagnosis (n = 4296). RESULTS: In multivariable-adjusted analyses, an elevated RMSSD (>100 ms) or IrrIx (>7.7%) was strongly associated with a higher risk of AF (hazard ratios (HRs) = 2.00-2.95) and cerebrovascular events (HRs = 1.91-2.28), even among people without prior AF diagnosis: HRs for AF = 1.70-2.05 and cerebrovascular events = 2.00-2.28. These associations were strongest in the highest RMSSD tertile >100 ms or IrrIx tertile >7.7%: HRs for AF = 2.32-4.47 and cerebrovascular events = 2.43-3.69. Among those without prior AF diagnosis, the highest categorical net reclassification improvement for 5-year cerebrovascular risk was 14% (95% confidence interval: 7-21%). CONCLUSIONS: Elevated RMSSD or IrrIx values indicative of the presence of AF predict future AF and cerebrovascular events; more so with increasing pulse irregularity and even among those without prior AF diagnosis.

Trends in the primary health care nursing workforce providing diabetes care in Auckland, New Zealand: A cross-sectional survey.

AIMS: To describe trends from 2006-8 to 2016 in demographic, education and work settings of the primary health care nursing workforce who provide diabetes care in the Auckland region. METHODS: A total of 1416 practice, Accident and Medical, district and diabetes specialist nurses were identified who provide community-based care. Of those, 459 were randomly selected and 336 were interviewed in 2016, and were compared with 287 nurses interviewed in 2006-8. RESULTS: A 73% response rate was attained in 2016. Compared with nurses in 2006-8, primary health care nurses in 2016 were younger, less experienced, more likely to be Asian, undertook more post-graduate education, worked more in Accident and Medical Clinics and worked in larger practices with ≥4 doctors. However, less worked with a dietitian or received visits from specialist nurses compared with nurses in 2006-8. Significantly more nurses in 2016 had their own room for administrative work and the ability to email patients suggesting greater autonomy. CONCLUSIONS: Major demographic, educational and workplace changes have occurred in the Auckland primary health care nursing workforce from 2006-8 to 2016. A significant increase in practice nurses and a large decrease in the number of diabetes specialist nurses were evident, in the Auckland region.

Relations of Demographic and Clinical Factors With Cardiovascular Autonomic Function in a Population-Based Study: An Assessment By Quantile Regression.

BACKGROUND: The relationships of many factors with cardiovascular autonomic function (CVAF) outcome parameters may not be uniform across the entire distribution of the outcome. We examined how demographic and clinical factors varied with different subgroups of CVAF parameters. METHODS: Quantile regression was applied to a cross-sectional analysis of 4,167 adults (56% male; age range, 50-84 years) from 4 ethnic groups (3,419 New Zealand European, 303 Pacific, 227 Maori, and 218 South Asian) and without diagnosed cardiac arrhythmia. Pulse rate variability (root mean square of successive differences (RMSSD) and SD of pulse intervals) and baroreflex sensitivity were response variables. Independent variables were age, sex, ethnicity, brachial and aortic blood pressure (BP) variables, body mass index (BMI), and diabetes. RESULTS: Ordinary linear regression showed that age, sex, Pacific and Maori ethnicity, BP variables, BMI, and diabetes were associated with CVAF parameters. But quantile regression revealed that, across CVAF percentiles, the slopes for these relationships: (i) varied by more than 10-fold in several cases and sometimes changed direction and (ii) noticeably differed in magnitude often (by >3-fold in several cases) compared to ordinary linear regression coefficients. For instance, age was inversely associated with RMSSD at the 10th percentile of this parameter (ß = -0.12 ms/year, 95% confidence interval = -0.18 to -0.09 ms/year) but had a positive relationship at the 90th percentile (ß = 3.17 ms/year, 95% confidence interval = 2.50 to 4.04 ms/year). CONCLUSIONS: The relationships of demographic and clinical factors with CVAF parameters are, in many cases, not uniform. Quantile regression provides an improved assessment of these associations.

Sun Exposure and Psychotic Experiences.

OBJECTIVE: Sun exposure is considered the single most important source of vitamin D. Vitamin D deficiency has been suggested to play a role in the etiology of psychotic disorders. The aim of the present study was to evaluate the association between sun exposure and psychotic experiences (PEs) in a general population sample of Swedish women. METHODS: The study population included participants from The Swedish Women's Lifestyle and Health cohort study. The 20-item community assessment of psychic experiences (CAPEs) was administered between ages 30 and 50 to establish PEs. Sun exposure as measured by (1) sunbathing holidays and (2) history of sunburn was measured between ages 10 and 39. The association between sun exposure and PEs was evaluated by quantile regression models. RESULTS: 34,297 women were included in the analysis. Women who reported no sunbathing holidays and 2 or more weeks of sunbathing holidays scored higher on the CAPE scale than women exposed to 1 week of sunbathing holidays across the entire distribution, when adjusting for age and education. Similarly, compared with women who reported a history of one sunburn, the women with none or two or more sunburns showed higher scores on the CAPE scale. CONCLUSION: The results of the present study suggest that, in a population-based cohort of middle aged women, both low and high sun exposure is associated with increased level of positive PEs.

Sun exposure and 25-hydroxyvitamin D3 levels in a community sample: Quantifying the association with electronic dosimeters.

There is uncertainty about the amount of sun exposure required to increase low blood 25-hydroxyvitamin D (25(OH)D3) levels, a possible disease risk factor. The study aimed to quantify the association between sun exposure and serum 25(OH)D3 concentrations in a multiethnic community sample (n=502) living in Auckland (37°S) and Dunedin (46°S), New Zealand, aged 18-85 years. They wore electronic ultraviolet dosimeters between March and November (autumn, winter and spring) for 8 weeks to record their sun exposure. This was converted to standard erythemal doses (SEDs), corrected for clothing to generate equivalent full-body exposures, SEDEFB. Blood samples were collected at the end of weeks 4 and 8 to measure 25(OH)D3. Median weekly SEDEFB was 0.33 during weeks 1-4 and 0.34 during weeks 5-8. Weekly exposures <0.5 SEDEFB during weeks 5-8 were associated with decreasing 25(OH)D3 concentrations at the end of week 8. There was a non-linear association between sun exposure and 25(OH)D3, with most of the increase in 25(OH)D3 being at exposures <2 SEDEFB per week. This finding suggests that vitamin D status is increased by regular small sun exposures (<2 SEDEFB per week), and that greater exposures result in only small additional increases in 25(OH)D3.

Different associations between beta-blockers and other antihypertensive medication combinations with brachial blood pressure and aortic waveform parameters.

BACKGROUND: Comparing the relationships of antihypertensive medications with brachial blood pressure (BP) and aortic waveform parameters may help clinicians to predict the effect on the latter in brachial BP-based antihypertensive therapy. We aimed to make such comparisons with new waveform measures and a wider range of antihypertensive regimens than examined previously. METHODS: Cross-sectional analysis of 2933 adults (61% male; aged 50-84years): 1637 on antihypertensive treatment and 1296 untreated hypertensives. Sixteen medicine regimens of up to 4 combinations of drugs from 6 antihypertensive classes were analysed. Aortic systolic BP, augmentation index (AIx), excess pressure integral (EPI), backward pressure amplitude (Pb), reflection index (RI) and pulse wave velocity (PWV) were calculated from aortic pressure waveforms derived from suprasystolic brachial measurement. RESULTS: Forest plots of single-drug class comparisons across regimens with the same number of drugs (for between 1- and 3-drug regimens) revealed that AIx, Pb, RI and/or loge(EPI) were higher (maximum difference=5.6%, 2.2mmHg, 0.0192 and 0.13 loge(mmHg⋅s), respectively) with the use of a beta-blocker compared with vasodilators and diuretics, despite no brachial systolic and diastolic BP differences. These differences were reduced (by 34-57%) or eliminated after adjustment for heart rate, and similar effects occurred when controlling for systolic ejection period or diastolic duration. CONCLUSIONS: Beta-blocker effects on brachial BP may overestimate effects on aortic waveform parameters. Compared to other antihypertensives, beta-blockers have weaker associations with wave reflection measures and EPI; this is predominantly due to influences on heart rate.

Factors associated with photoprotection by body clothing coverage, particularly in non-summer months, among a New Zealand community sample.

Clothing coverage is important for reducing skin cancer risk, but may also influence vitamin D sufficiency, so associated plausible predictors require investigation. Volunteers (18 to 85 years), with approximately equal numbers by sex and four ethnicity groups, were recruited in cities from two latitude bands: Auckland (36.9°S) and Dunedin (45.9°S). Baseline questionnaire, anthropometric and spectrophotometer skin colour data were collected and weather data obtained. Percent body coverage was calculated from eight week diary records. Potential independent predictors (unadjusted p < 0.25) were included in adjusted models. Participants (n = 506: Auckland n = 334, Dunedin n = 172; mean age 48.4 years) were 62.7% female and had a median body clothing coverage of 81.6% (IQR 9.3%). Dunedin was cooler, less windy and had lower UVI levels than Auckland. From the fully adjusted model, increased coverage occurred in non-summer months (despite adjusting for weather), among Dunedin residents and Asians (compared to Europeans), during the middle of the day, with a dose response effect observed for greater age. Reduced coverage was associated with Pacific ethnicity and greater time spent outdoors. Additionally, higher temperatures were associated with reduced coverage, whereas increased cloud cover and wind speed were associated with increased coverage. Although the only potentially modifiable factors associated with clothing coverage were the time period and time spent outdoors, knowledge of these and other associated factors is useful for the framing and targeting of health promotion messages to potentially influence clothing coverage, facilitate erythema avoidance and maintain vitamin D sufficiency.

Statin utilisation in a real-world setting: a retrospective analysis in relation to arterial and cardiovascular autonomic function.

Randomized trials suggest that statin treatment may lower blood pressure and influence cardiovascular autonomic function (CVAF), but the impact of duration of usage, discontinuation, and adherence to this therapy is unknown. We examined these issues with regard to blood pressure (BP)-related variables in a large, population-based study. Participants were 4942 adults (58% male; aged 50-84 years): 2179 on statin treatment and 2763 untreated. Days of utilization, adherence (proportion of days covered ≥0.8), and discontinuation (non-use for ≥30 days immediately prior to BP measurement) of three statins (atorvastatin, pravastatin, and simvastatin) over a period of up to 2 years was monitored retrospectively from electronic databases. Systolic BP (SBP), diastolic BP (DBP), augmentation index, excess pressure, reservoir pressure, and CVAF (pulse rate and BP variability) parameters were calculated from aortic pressure waveforms derived from suprasystolic brachial measurement. Days of statin treatment had inverse relationships with pulse rate variability parameters in cardiac arrhythmic participants (20-25% lower than in statin non-users) and with most arterial function parameters in everyone. For example, compared to untreated participants, those treated for ≥659 days had 3.0 mmHg lower aortic SBP (P < 0.01). Discontinuation was associated with higher brachial DBP and aortic DBP (for both, ß = 2.0 mmHg, P = 0.008). Compared to non-adherent statin users, adherent users had lower levels of brachial SBP, brachial DBP, aortic DBP, aortic SBP, and peak reservoir pressure (ß = -1.4 to -2.6 mmHg). In conclusion, in a real-world setting, statin-therapy duration, non-discontinuation and adherence associate inversely with BP variables and, in cardiac arrhythmias, CVAF parameters.

Consistent ethnic specific differences in diabetes risk and vitamin D status in the National Health and Nutrition Examination Surveys.

Previous findings from the Third National Health and Nutrition Examination Survey (NHANES III), a representative sample of the US population carried out in 1988-1994, showed an inverse association between diabetes risk and serum concentrations of 25-hydroxyvitamin D (25(OH)D) in non-Hispanic whites and Mexican-Americans but not in non-Hispanic blacks. The study aim was to determine if this same pattern in ethnic variation occurred in more recent NHANES surveys. Cross-sectional data came from the NHANES carried out from 1988 to 1994 (NHANES III) and from 2001 to 2006 (NHANES 01-06). The analysis included 11,331 people (5641 non-Hispanic white, 2714 non-Hispanic black and 2976 Mexican American) without known diabetes mellitus, fasting for ≥8h and aged ≥20 years, with available measurements of 25(OH)D, fasting glucose, fasting insulin and body mass index (BMI). Adjusting for age, gender, BMI, leisure time physical activity and season, higher levels of 25(OH)D were associated with decreased fasting glucose, decreased fasting insulin, and decreased diabetes risk in both non-Hispanic whites and Mexican Americans for both surveys and when combined. When combining NHANES III and NHANES 01-06 the odds ratio (95% confidence interval) for having diabetes was 0.28 (0.19, 0.41) in the highest 25(OH)D quartile compared to the lowest quartile in non-Hispanic whites, and 0.13 (0.06, 0.28) in Mexican Americans (both p<0.0001); but 1.54 (0.62, 3.82) in non-Hispanic blacks, among whom 25(OH)D was not associated with fasting glucose, fasting insulin, or diabetes risk (p>0.05). There was a significant interaction between non-Hispanic whites and Mexican Americans combined, compared with non-Hispanic blacks, when 25(OH)D was regressed against fasting glucose (p=0.016) but not against fasting insulin (p>0.05). The major finding in both NHANES surveys of consistent inverse associations between serum 25(OH)D concentrations and diabetes risk in non-Hispanic whites and Mexican Americans, but not in non-Hispanic blacks, suggests this finding is unlikely due to chance.

Light to moderate alcohol consumption is protective for type 2 diabetes mellitus in normal weight and overweight individuals but not the obese.

OBJECTIVE: To examine the association between alcohol consumption and risk of type 2 diabetes mellitus (T2DM) overall and by body mass index. METHODS: Cross-sectional study of employed individuals. Daily alcohol intakes were calculated from a self-administered food frequency questionnaire by 5,512 Maori, Pacific Island, and European workers (3,992 men, 1520 women) aged 40 years and above. RESULTS: There were 170 new cases of T2DM. Compared to the group with no alcohol consumption and adjusting for age, sex, and ethnicity, the group consuming alcohol had relative risks of T2DM of 0.23 (95% CI: 0.08, 0.65) in normal weight individuals, 0.38 (0.18, 0.81) in overweight individuals, and 0.99 (0.59, 1.67) in obese individuals. After further adjusting for total cholesterol, HDL-cholesterol, triglycerides, smoking habit, physical activity, socioeconomic status, body mass index, and hypertension, the relative risks of T2DM were 0.16 (0.05, 0.50) in normal weight individuals, 0.43 (0.19, 0.97) in overweight individuals, and 0.92 (0.52, 1.60) in overweight individuals. Across the categories of alcohol consumption, there was an approximate U-shaped relationship for new cases of T2DM. There was no significant association between alcohol consumption and IGT. CONCLUSIONS: Alcohol consumption was protective against diagnosis of T2DM in normal and overweight individuals but not in the obese.

Sizing the association between lifestyle behaviours and fatness in a large, heterogeneous sample of youth of multiple ethnicities from 4 countries.

BACKGROUND: The magnitude of the relationship between lifestyle risk factors for obesity and adiposity is not clear. The aim of this study was to clarify this in order to determine the level of importance of lifestyle factors in obesity aetiology. METHODS: A cross-sectional analysis was carried out on data on youth who were not trying to change weight (n = 5714), aged 12 to 22 years and from 8 ethnic groups living in New Zealand, Australia, Fiji and Tonga. Demographic and lifestyle data were measured by questionnaires. Fatness was measured by body mass index (BMI), BMI z-score and bioimpedance analysis, which was used to estimate percent body fat and total fat mass (TFM). Associations between lifestyle and body composition variables were examined using linear regression and forest plots. RESULTS: TV watching was positively related to fatness in a dose-dependent manner. Strong, dose-dependent associations were observed between fatness and soft drink consumption (positive relationship), breakfast consumption (inverse relationship) and after-school physical activity (inverse relationship). Breakfast consumption-fatness associations varied in size across ethnic groups. Lifestyle risk factors for obesity were associated with percentage differences in body composition variables that were greatest for TFM and smallest for BMI. CONCLUSIONS: Lifestyle factors were most strongly related to TFM, which suggests that studies that use BMI alone to quantify fatness underestimate the full effect of lifestyle on adiposity. This study clarifies the size of lifestyle-fatness relationships observed in previous studies.

Association of 25-hydroxyvitamin D3)levels in adult New Zealanders with ethnicity, skin color and self-reported skin sensitivity to sun exposure.

The study aim was to determine the contribution of ethnicity, objectively measured skin color and skin reaction-to-sun exposure to variations in 25-hydroxyvitamin D(3) [25(OH)D(3) ]. A multiethnic sample (European, Maori, Pacific and Asian) of 503 adult volunteers aged 18-85 years, recruited from Auckland and Dunedin in New Zealand, answered a questionnaire on sun exposure and self-defined ethnicity. Skin color was measured using a spectrophotometer and the Individual Typology Angle (ITA) calculated. A blood sample was collected 4 weeks later to measure 25(OH)D(3). 25(OH)D(3) was associated with ethnicity, but not self-reported skin reaction-to-sun exposure. Amongst the ethnic groups, Asians had the lowest mean 25(OH)D level (37.0 nmol L(-1)) and Europeans with lighter colored skin had the highest (57.9 nmol L(-1)). An association also was seen between 25(OH)D(3) and skin color, with an increase of 2-3 nmol L(-1) per 10° increase in ITA value, indicating higher 25(OH)D(3) with lighter skin color; but much of this association disappeared after adjusting for ethnicity. In contrast, ethnicity remained associated with 25(OH)D(3) after adjusting for ITA skin color and skin reaction-to-sun exposure. These results indicate that self-defined ethnicity was a major determinant of variations in serum 25(OH)D(3), while objective measures of skin color explained relatively little additional variation.

Vitamin D, parathyroid hormone, and blood pressure in the National Health and Nutrition Examination Surveys .

BACKGROUND: Previous research shows serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) are each associated with blood pressure (BP), but it is unclear whether these associations are independent. METHODS: Cross-sectional data from the US National Health and Nutrition Examination Surveys (NHANES) during 2003-2006. Analyses were restricted to 7,561 participants aged ≥20 years with measurements of 25(OH)D, PTH, BP, BP treatment, smoking, physical activity, serum calcium, and creatinine. Results were adjusted for these plus demographic variables. RESULTS: Serum 25(OH)D was more strongly associated (inversely) with systolic than diastolic BP. Adjusted mean (standard error) difference in BP for the lowest 25(OH)D quintile (≤13 ng/ml) was 3.5 (0.7) mm Hg for systolic BP and 1.8 (0.6) mm Hg for diastolic BP, compared with the highest quintile (≥30 ng/ml). In contrast, PTH was positively associated with both systolic and diastolic BP (P < 0.0001). Adjusted mean (standard error) difference in BP for the highest PTH quintile (≥59 ng/l) was 5.9 (0.8) mm Hg for systolic BP and 4.5 (0.5) mm Hg for diastolic BP, compared with the lowest quintile (≤27 ng/l). When both 25(OH)D and PTH were included in the same model, the associations of PTH with systolic and diastolic BP were unchanged. However, the associations between 25(OH)D and BP were attenuated, with mean (standard error) difference between the highest and lowest quintiles being 2.2 (0.6) mm Hg for systolic BP (P < 0.01) and 0.8 (0.6) mm Hg for diastolic BP. CONCLUSION: PTH may mediate most of the association between 25(OH)D and BP, which was not significant when also adjusting for body mass index.

Body mass index and percent body fat in a New Zealand multi-ethnic adolescent population.

Abstract Objective. Previous studies show that body mass index (BMI) does not fully explain differences in percent body fat (%BF) between ethnic groups and few studies have investigated this in adolescents. We sought to compare %BF for a given BMI between adolescents from four ethnic groups and to explain ethnic differences in this relationship. Methods. Weight, height and waist circumference were measured in 202 boys and 197 girls (age range 12-19 years; 129 Pacific Island, 91 European, 90 Maori and 89 Asian Indian). Fat mass, appendicular skeletal muscle mass (ASMM), leg length, bone mineral content (BMC), and fat distribution measures were derived from dual-energy X-ray absorptiometry. Results. For the same BMI and age, compared with European boys, %BF in Maori, Pacific Island and Asian Indian boys was 2.8% lower (P=0.017), 5.2% lower (P<0.0001), and 3.5% higher (P=0.0025), respectively. Compared with European girls, %BF, adjusted for BMI, for Maori, Pacific Island and Asian Indian girls was 1.9% lower (P=0.024), 4.1% lower (P<0.0001) and 3.6% higher (P<0.0001), respectively. Adjustment for ASMM, BMC and fat distribution variables, in particular, significantly reduced the differences between ethnic groups. In boys, readily measured variables, conicity index and waist circumference/height, had notable effects on ethnic differences in %BF. Conclusions. Our results show that BMI is not an equivalent measure of %BF between adolescent Europeans, Maori, Pacific Islanders and Asian Indians. Differences in muscularity, bone mass, relative leg length, fat distribution and body shape contribute to this disparity.

Dietary intakes of Pacific, Maori, Asian and European adolescents: the Auckland High School Heart Survey.

OBJECTIVE: To compare dietary intakes of European, Maori, Pacific Island and Asian adolescents living in Auckland. METHODS: A self-administered food frequency questionnaire was used to assess daily nutrient intakes of 2,549 14- to 21-year-old high-school students in Auckland (1,422 male and 1,127 female) in a cross-sectional survey carried out between 1997 and 1998. RESULTS: Compared with Europeans, Maori and Pacific Islanders consumed more energy per day. Carbohydrate, protein and fat intakes were higher in Maori and Pacific Islanders than in Europeans. Cholesterol intakes were lowest in Europeans and alcohol intakes were highest in Europeans and Maori. When nutrient intakes were expressed as their percentage contribution to total energy, many ethnic differences in nutrient intakes between Europeans and Maori or Pacific Islanders were eliminated. After adjustment for energy intake and age, Europeans ate the fewest eggs, and Pacific Islanders and Asians ate more servings of chicken and fish, and fewer servings of milk and cereal than Europeans. Compared to Europeans, Pacific Islanders consumed larger portion sizes for nearly every food item. CONCLUSION: There were marked differences in nutrient intakes between Pacific, Maori, Asian and European adolescents. Ethnic differences in food selections, frequency of food servings and portion sizes contribute to the differences in nutrient intakes between these ethnic groups. These differences generally matched those of other studies in children and adults from these ethnic groups. IMPLICATIONS: Interventions that reduce frequency of food consumption and serving sizes and promote less-fatty food choices in Maori and Pacific adolescents are needed.

Relation of serum 25-hydroxyvitamin D to heart rate and cardiac work (from the National Health and Nutrition Examination Surveys).

Vitamin D may protect against cardiovascular disease, but its association with cardiac function is unclear. The aim of this study was to examine the associations of serum 25-hydroxyvitamin D (25[OH]D) with heart rate, systolic blood pressure, and the rate-pressure product (RPP). Data analyses were carried out on 27,153 participants aged > or =20 years, with measurements of serum 25(OH)D, heart rate (from radial pulse), and systolic blood pressure, in the National Health and Nutrition Examination Surveys (NHANES) carried out from 1988 to 1994 and from 2001 to 2006. RPP was calculated as heart rate times systolic blood pressure. Results were adjusted for age, gender, race or ethnicity, body mass index, physical activity, tobacco smoking, co-morbidities, and blood pressure treatment. Compared to participants with 25(OH)D > or =35 ng/ml, the adjusted mean +/- SE heart rate was significantly (p <0.001) higher, by 2.1 +/- 0.6 beats/min, in participants with 25(OH)D <10.0 ng/ml, while mean systolic blood pressure was 1.9 +/- 0.8 mm Hg higher (p <0.05) for participants with 25(OH)D <10.0 ng/ml and 1.7 +/- 0.6 mm Hg higher (p <0.01) for those with 25(OH)D of 10.0 to 14.9 ng/ml. As a consequence, adjusted mean RPP was 408 +/- 110 beats/min . mm Hg higher (p <0.001) for participants with 25(OH)D <10.0 ng/ml and 245 +/- 80 beats/min . mm Hg higher (p <0.01) for participants with 25(OH)D of 10.0 to 14.9 ng/ml, compared to those with 25(OH)D > or =35 ng/ml. In conclusion, these results show that low serum 25(OH)D levels are associated with increased heart rate, systolic blood pressure, and RPP and suggest that low vitamin D status may increase cardiac work. Vitamin D intervention studies are required to confirm these findings.