Seasonal variation in parameters related to coronary heart disease risk in young men

Relationship of Ambient Temperature Parameters to Stroke Incidence in a Japanese Population - Takashima Stroke Registry, Japan, 1988-2010

BACKGROUND

Using a population-based stroke registry system, we evaluated the relationship between ambient temperature parameters and stroke incidence in a Japanese population.

METHODS AND RESULTS

We analyzed data from the Takashima Stroke Registry, which records all stroke occurrences in Takashima City, Japan. The study period of 8,401 days was divided into quintiles of daily weather parameters, and the middle quintile was used as the reference category. Incidence rates (IR per 100,000 person-years) were calculated across the quintiles. Poisson regression analysis was used to calculate the effect of temperature parameters on stroke incidence. There were 2,405 first-ever strokes (1,294 men), including 1,625 ischemic, 545 cerebral hemorrhages, 213 subarachnoid hemorrhages, and 22 unclassified strokes. The stroke IR was higher in the middle quintile of average temperature, 357.3 (328.4-388.8), and for other parameters. After adjustment for age and sex, for all stroke, the incidence rate ratio (IRR) in the highest (Q5: IRR 0.81, 95% confidence interval (CI) 0.71-0.92) and the second-highest (Q4: IRR 0.80, 95% CI 0.71-0.91) quintile was lower than that in the middle quintile (Q3: Reference). Analogous results were observed for the minimum, maximum, and lag-days temperatures, also in the subtypes and across ≥65 years of age, also in females.

CONCLUSIONS

Higher temperatures, irrespective of the parameter (average, minimum, or maximum), had a protective effect against stroke occurrence in Japan.

Sequential recruitment of study participants may inflate genetic heritability estimates

After the success of genome-wide association studies to uncover complex trait loci, attempts to explain the remaining genetic heritability (h ²) are mainly focused on unraveling rare variant associations and gene-gene or gene-environment interactions. Little attention is paid to the possibility that h ² estimates are inflated as a consequence of the epidemiological study design. We studied the time series of 54 biochemical traits in 4373 individuals from the Cooperative Health Research In South Tyrol (CHRIS) study, a pedigree-based study enrolling ten participants/day over several years, with close relatives preferentially invited within the same day. We observed distributional changes of measured traits over time. We hypothesized that the combination of such changes with the pedigree structure might generate a shared-environment component with consequent h ² inflation. We performed variance components (VC) h ² estimation for all traits after accounting for the enrollment period in a linear mixed model (two-stage approach). Accounting for the enrollment period caused a median h ² reduction of 4%. For 9 traits, the reduction was of >20%. Results were confirmed by a Bayesian Markov chain Monte Carlo analysis with all VCs included at the same time (one-stage approach). The electrolytes were the traits most affected by the enrollment period. The h ² inflation was independent of the h ² magnitude, laboratory protocol changes, and length of the enrollment period. The enrollment process may induce shared-environment effects even under very stringent and standardized operating procedures, causing h ² inflation. Including the day of participation as a random effect is a sensitive way to avoid overestimation.

Harvest for health gardening intervention feasibility study in cancer survivors

BACKGROUND

Cancer survivors are at increased risk for second malignancies, cardiovascular disease, diabetes, and functional decline. Evidence suggests that a healthful diet and physical activity may reduce the risk of chronic disease and improve health in this population.

METHODS

We conducted a feasibility study to evaluate a vegetable gardening intervention that paired 12 adult and child cancer survivors with Master Gardeners to explore effects on fruit and vegetable intake, physical activity, quality-of-life, and physical function. Throughout the year-long study period, the survivor-Master Gardener dyads worked together to plan/plant three gardens, harvest/rotate plantings, and troubleshoot/correct problems. Data on diet, physical activity, and quality-of-life were collected via surveys; anthropometrics and physical function were objectively measured. Acceptability of the intervention was assessed with a structured debriefing survey.

RESULTS

The gardening intervention was feasible (robust enrollment; minimal attrition) and well-received by cancer survivors and Master Gardeners. Improvement in three of four objective measures of strength, agility, and endurance was observed in 90% of survivors, with the following change scores [median (interquartile range)] noted between baseline and one-year follow-up: hand grip test [+ 4.8 (3.0, 6.7) kg], 2.44 meter Get-Up-and-Go [+ 1.0 (+ 1.8, + 0.2) seconds], 30-second chair stand [+ 3.0 (+ 1.0, 5.0) stands], and six-minute walk [+ 11.6 (6.1, 48.8) meters]. Increases of ≥ 1 fruit and vegetable serving/day and ≥ 30 minutes/week of physical activity were observed in 40% and 60%, respectively.

CONCLUSION

These preliminary results support the feasibility and acceptability of a mentored gardening intervention and suggest that it may offer a novel and promising strategy to improve fruit and vegetable consumption, physical activity, and physical function in cancer survivors. A larger randomized controlled trial is needed to confirm our results.

Static platelet adhesion, flow cytometry and serum TXB2 levels for monitoring platelet inhibiting treatment with ASA and clopidogrel in coronary artery disease: a randomised cross-over study

Background

Despite the use of anti-platelet agents such as acetylsalicylic acid (ASA) and clopidogrel in coronary heart disease, some patients continue to suffer from atherothrombosis. This has stimulated development of platelet function assays to monitor treatment effects. However, it is still not recommended to change treatment based on results from platelet function assays. This study aimed to evaluate the capacity of a static platelet adhesion assay to detect platelet inhibiting effects of ASA and clopidogrel. The adhesion assay measures several aspects of platelet adhesion simultaneously, which increases the probability of finding conditions sensitive for anti-platelet treatment.

Methods

With a randomised cross-over design we evaluated the anti-platelet effects of ASA combined with clopidogrel as well as monotherapy with either drug alone in 29 patients with a recent acute coronary syndrome. Also, 29 matched healthy controls were included to evaluate intra-individual variability over time. Platelet function was measured by flow cytometry, serum thromboxane B₂ (TXB₂)-levels and by static platelet adhesion to different protein surfaces. The results were subjected to Principal Component Analysis followed by ANOVA, t-tests and linear regression analysis.

Results

The majority of platelet adhesion measures were reproducible in controls over time denoting that the assay can monitor platelet activity. Adenosine 5'-diphosphate (ADP)-induced platelet adhesion decreased significantly upon treatment with clopidogrel compared to ASA. Flow cytometric measurements showed the same pattern (r² = 0.49). In opposite, TXB₂-levels decreased with ASA compared to clopidogrel. Serum TXB₂ and ADP-induced platelet activation could both be regarded as direct measures of the pharmacodynamic effects of ASA and clopidogrel respectively. Indirect pharmacodynamic measures such as adhesion to albumin induced by various soluble activators as well as SFLLRN-induced activation measured by flow cytometry were lower for clopidogrel compared to ASA. Furthermore, adhesion to collagen was lower for ASA and clopidogrel combined compared with either drug alone.

Conclusion

The indirect pharmacodynamic measures of the effects of ASA and clopidogrel might be used together with ADP-induced activation and serum TXB₂ for evaluation of anti-platelet treatment. This should be further evaluated in future clinical studies where screening opportunities with the adhesion assay will be optimised towards increased sensitivity to anti-platelet treatment.

Seasonal variation in lipids in patients following acute coronary syndrome on fixed doses of Pravastatin (40 mg) or Atorvastatin (80 mg) (from the Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis In Myocardial Infarction 22 [PROVE IT-TIMI 22] Study)

Previous studies have shown seasonal variation in lipids. To understand whether this variation exists in patients with acute coronary syndromes receiving statins, we examined data from the PROVE IT-TIMI 22 Study. At baseline, no significant difference in low-density lipoprotein (LDL) cholesterol was observed when stratified by season. However, a statistically significant difference in high-density lipoprotein cholesterol between winter (37 mg/dl) and summer (39 mg/dl) was observed (p <0.001) at baseline. On treatment, median LDL cholesterol was 102 mg/dl in winter versus 96 mg/dl in summer (p <0.001) for the pravastatin group and 68 mg/dl in winter versus 62 mg/dl in summer (p <0.001) for the atorvastatin group. Median high-density lipoprotein cholesterol was 43 mg/dl in summer versus 41 mg/dl in winter in the pravastatin group and 42 mg/dl in summer versus 39 mg/dl in winter in the atorvastatin group (p <0.001). More patients achieved LDL cholesterol <100 mg/dl in summer at 56% versus 47% in winter in the pravastatin group (p <0.001) and 89% versus 87% in winter for the atorvastatin group (p = 0.11). Achievement of LDL cholesterol <70 mg/dl was also higher in summer than winter. In conclusion, this was the first evidence of seasonal variability in cholesterol in patients with acute coronary syndromes treated with statins. This variability affected achievement of National Cholesterol Education Program goals and may affect management decisions based on season of collection.

Main Outcomes of the FRESH START Trial: A Sequentially Tailored, Diet and Exercise Mailed Print Intervention Among Breast and Prostate Cancer Survivors

Purpose

Cancer survivors are at increased risk for cardiovascular disease, diabetes, osteoporosis, and second primary tumors. Healthful lifestyle practices may improve the health and well-being of survivors. The FRESH START trial tested the efficacy of sequentially tailored versus standardized mailed materials on improving cancer survivors’ diet and exercise behaviors.

Methods

Five hundred forty-three individuals with newly diagnosed locoregional breast or prostate cancer were recruited from 39 states and two provinces within North America. Participants were randomly assigned either to a 10-month program of tailored mailed print materials promoting fruit and vegetable (F&V) consumption, reducing total/saturated fat intake, and/or increasing exercise or to a 10-month program of nontailored mailed materials on diet and exercise available in the public domain. Telephone surveys conducted at baseline and 1 year assessed body mass index (BMI), dietary consumption, physical activity, and other psychosocial/behavioral indices. Clinical assessments were conducted on a 23% subsample; information was used to validate self-reports.

Results

Five hundred nineteen participants completed the 1-year follow-up (4.4% attrition; sample characteristics: 57 ± 10.8 years old, 83% white, 56% female, 64% overweight/obese, and 0% underweight). Although both arms significantly improved their lifestyle behaviors (P < .05), significantly greater gains occurred in the FRESH START intervention versus the control arm (practice of two or more goal behaviors: +34% v +18%, P < .0001; exercise minutes per week: +59.3 v +39.2 minutes, P = .02; F&V per day: +1.1 v +0.6 servings, P = .01; total fat: −4.4% v –2.1%, P < .0001; saturated fat: −1.3% v –0.3%, P < .0001; and BMI: −0.3 v +0.1 kg/m2, respectively, P = .004).

Conclusion

Mailed material interventions, especially those that are tailored, are effective in promoting healthful lifestyle changes among cancer survivors. Further study is needed to determine sustainability, cost to benefit, and generalizability to other cancer populations.

Community-based study on summer-winter differences of component of metabolic syndrome in Kinmen, Taiwan

BACKGROUND

A community-based study was conducted to investigate summer-winter differences of component of metabolic syndrome in Kinmen, Taiwan.

METHODS

A total of 8251 residents aged 40 and over were enrolled in the mass survey in Kinmen. They were investigated while on summer (July and August) and winter vacation (January and February) during 2000-2003. Demographics, physical examination findings, lifestyle variables and biochemical data were collected.

RESULTS

After controlling for age, body mass index, diet, lifestyle and other risk factors for component of metabolic syndrome, there were independent and significant relationships between summer-winter difference and component of metabolic syndrome. Winter season was positively correlated with blood pressure, fasting plasma glucose level, high-density lipoprotein-cholesterol (HDL-C) and waist circumference, but was negatively associated with fasting triglycerides and metabolic syndrome.

CONCLUSIONS

Summer season is positively associated with hypertriglyceridemia, low HDL-C and metabolic syndrome. These findings imply that cross-sectional, experimental and cohort studies of component of metabolic syndrome or metabolic syndrome should take season into account as possible confounding effects.

Seasonal patterns in monthly hemoglobin A1c values

The purpose of this study was to investigate seasonal variations in population monthly hemoglobin A(1c) (A1c) values over 2 years (from October 1998 to September 2000) among US diabetic veterans. The study cohort included 285,705 veterans with 856,181 A1c tests. The authors calculated the monthly average A1c values for the overall population and for subpopulations defined by age, sex, race, insulin use, and climate regions. A1c values were higher in winter and lower in summer with a difference of 0.22. The proportion of A1c values greater than 9.0% followed a similar seasonal pattern that varied from 17.3% to 25.3%. Seasonal autoregressive models including trigonometric function terms were fit to the monthly average A1c values. There were significant seasonal effects; the seasonal variation was consistent across different subpopulations. Regions with colder winter temperatures had larger winter-summer contrasts than did those with warmer winter temperatures. The seasonal patterns followed trends similar to those of many physiologic markers, cardiovascular and other diabetes outcomes, and mortality. These findings have implications for health-care service research in quality-of-care assessment, epidemiologic studies investigating population trends and risk factors, and clinical trials or program evaluations of treatments or interventions.

Cholesterol bound to hemoglobin in normal human erythrocytes: a new form of cholesterol in circulation?

OBJECTIVE

To study lipid fraction that is occasionally observed in red blood cell (RBC) hemolysate (supernatants from which membranes were separated).

STUDY DESIGN

Plasma lipid profiles, cholesterol (Ch) and phospholipids (PL) in intact RBCs, RBC membranes and hemolysates were examined in young healthy male population in winter and summer.

RESULTS

The RBC Ch and PL content was significantly higher than in membranes, both in winter and summer. The "excess" of cholesterol (associated with phospholipid) was bound to hemoglobin yielding Hb-lipid adduct (Hb-Ch), the pools in the RBC membrane remaining virtually unaltered. Levels of hemoglobin-lipid complex (Hb-Ch), which were significantly higher in winter than in summer (30% and 19% of the total Hb, respectively), positively correlated with plasma HDL cholesterol levels.

CONCLUSION

To our knowledge, this is the first demonstration of cholesterol binding to Hb. The results suggest influence of plasma lipoprotein metabolism on the formation of Hb-Ch.

Design of FRESH START: a randomized trial of exercise and diet among cancer survivors

PURPOSE

FRESH START is a randomized controlled trial that will test whether a personally tailored, distance-medicine-based program will increase exercise and fruit and vegetable consumption, and decrease fat intake of individuals recently diagnosed with breast or prostate cancer.

METHODS

Early-stage breast and prostate cancer cases (N= 530) will be identified within 9 months of diagnosis from hospital cancer registries and large oncologic practices throughout the United States. These individuals will be sent a letter of invitation and screened for eligibility. After a baseline telephone interview, participants will be randomized into one of two arms that receive materials aimed at increasing exercise and fruit and vegetable intake, and decreasing dietary fat: 1). an experimental arm that receives a workbook and a series of six 4-page newsletters delivered every 7 wk and personally tailored on type of cancer, cancer coping style, race, age, self-efficacy, stage of readiness, and barriers and/or progress toward goal behavior (i.e., >or= 30 min of exercise at least 5 d.wk, >or= 5 servings of vegetables and fruit per day, and <or= 30% of calories from fat); or 2). a control arm that receives a series of nontailored health brochures. Follow-up interviews scheduled 1 and 2 yr postbaseline will determine short- and long-term efficacy and the effects of the interventions on other endpoints (quality of life, perceived health, etc.). Factors, such as gender, race, and social support, also will be explored to determine potential interactions with program efficacy.

CONCLUSION

Given the growing number of cancer survivors, distance-medicine-based interventions addressing multiple behaviors and targeting this high-risk group have the potential to make a positive and broad public health impact.

Seasonality of coronary artery deaths in New South Wales, Australia

BACKGROUND

Complex temporal variations in coronary deaths, including diurnal, weekly, and seasonal trends, have been reported worldwide.

OBJECTIVE

To describe the magnitude of seasonal changes in coronary artery deaths in New South Wales, Australia.

DESIGN

Hospital morbidity data, mortality statistics, and meteorological data were modelled using time series techniques to determine seasonality of coronary deaths. Data were also analysed to determine whether there was an increase in deaths before or after the Christmas and New Year holidays.

RESULTS

A clear seasonality of coronary deaths was shown, with a peak in July. A mean of 2.8 excess coronary deaths per 100 deaths was estimated to occur from June to August each year, with a mean annual excess of 224 winter deaths a year. Mortality data did not show an increase in coronary death ratios before (p = 0.626) or after (p = 0.813) the Christmas and New Year holidays in December.

CONCLUSIONS

There is a higher incidence of coronary deaths in winter, which may reflect winter respiratory infections, the direct effect of cold, seasonal changes in lipid concentration, and other factors associated with winter. Hospitals should have contingency plans during the winter months to manage larger numbers of cardiac admissions.

Influence of photoperiod, laboratory caging and aging on plasma lipid response to an atherogenic diet among F1B hamsters

The effects and interactions of photoperiod, animal caging, aging and diet on plasma lipid levels in male F1B hamsters were examined in the current study. Sixteen young and sixteen old animals were housed one or four per cage. Eight young animals from each housing group were placed in an animal room with either 12/12 h (PT-12) or 10/14 h (PT-10) light/dark cycle while the sixteen old animals were maintained under a PT-12 light cycle. Plasma cholesterol and triglyceride concentrations were determined in all animals after a 2-week period of acclimation on chow diet and following 4-week intervention on atherogenic diet. Baseline total cholesterol (TC) levels were 131+/-25 mg/dl and 142+/-39 mg/dl for young and old animals, respectively, while baseline triglyceride (Tg) levels were 202+/-48 mg/dl and 160+/-37 mg/dl respectively for the same animals. Following 4-weeks on an atherogenic diet, single-caged PT 12 animals had elevated but significantly lower TC levels than group-caged animals (161+/-30 mg/dl and 240 +/-58 mg/dl, respectively) while single and group housed PT10 animals had TC levels of 296+/-75 mg/dl and 351+/-124 mg/dl, respectively. Similarly, plasma Tg levels rose to 330+/-100 mg/dl and 486+/-200 mg/dl in single and group housed PT12 animals (respectively) and to 668+/-270 mg/dl and 545+/-199 mg/dl in single and group housed PT10 animals (respectively). No significant changes related to atherogenic diet were observed in plasma TC or Tg levels in the older animals. Although caging conditions influence the cholesterol and triglyceride response to the atherogenic diet (p<.05), light cycle photoperiod seems to exert a greater effect (p<.005). In conclusion, photoperiod length dramatically affects diet-induced plasma lipid concentrations in young male F1B hamsters, and thus needs be considered in experimental designs of animal-housed lipid research.

Influence of dietary intake and physical activity on annual rhythm of human blood cholesterol concentrations

Seasonal variation in the plasma total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) have been repeatedly reported, with contradictory results regarding the pattern of seasonal variation of these parameters. Furthermore, it is still not well established whether the variation is due to changes in the nutrition or changes in physical activity depending on the season. The aim of this study was therefore to determine plasma TC and HDL-C in different groups of healthy participants: 19 vegetarians with a constant diet independent of the season, 14 athletes with almost constant physical activity over the year, and 114 controls in the age groups 20-26 years (mean age 24 + 1.5 years) and 40-48 years (mean age 44.3 + 2.1 years). Over 2 years, blood samples were collected every 2-3 months and were analyzed for plasma TC and HDL-C. At all visits, body mass index (BMI) and waist-to-hip ratio (WHR) were calculated, and nutrition and physical activity profiles were obtained. The seasonal model was calculated using object-oriented software for the analysis of longitudinal data in S (OSWALD); multiple regression analysis was used to determine the influence of age, gender, diet, and physical activity on seasonal changes of the lipid parameters. In all groups, we found an annual rhythm of the plasma TC and HDL-C concentrations, which can be mathematically described by a sine curve with a maximum in winter and a minimum in summer. This rhythm was independent of the age, gender, BMI, diet, or physical activity. The observed seasonal differences between the maximum and the minimum were about 5%-10% for TC and about 5%-8% for HDL-C concentration. These differences were greater than the determined circadian (TC 3.5%, HDL-C 4%) and day-to-day changes for TC and HDL-C (coefficient of variation <5% for both). In conclusion, annual rhythm of TC and HDL-C is not primarily induced by seasonal differences in dietary intake or physical activity. Therefore, the annual rhythm in cholesterol levels is most likely determined by endogenous factors or factors directly related to seasonal changes in the environment.

Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. The Carbohydrate Ratio Management in European National diets

OBJECTIVE

To investigate the long-term effects of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates.

DESIGN

Randomized controlled multicentre trial (CARMEN), in which subjects were allocated for 6 months either to a seasonal control group (no intervention) or to one of three experimental groups: a control diet group (dietary intervention typical of the average national intake); a low-fat high simple carbohydrate group; or a low-fat high complex carbohydrate group.

SUBJECTS

Three hundred and ninety eight moderately obese adults.

MEASUREMENTS

The change in body weight was the primary outcome; changes in body composition and blood lipids were secondary outcomes.

RESULTS

Body weight loss in the low-fat high simple carbohydrate and low-fat high complex carbohydrate groups was 0.9 kg (P < 0.05) and 1.8 kg (P < 0.001), while the control diet and seasonal control groups gained weight (0.8 and 0.1 kg, NS). Fat mass changed by -1.3kg (P< 0.01), -1.8kg (P< 0.001) and +0.6kg (NS) in the low-fat high simple carbohydrate, low-fat high complex carbohydrate and control diet groups, respectively. Changes in blood lipids did not differ significantly between the dietary treatment groups.

CONCLUSION

Our findings suggest that reduction of fat intake results in a modest but significant reduction in body weight and body fatness. The concomitant increase in either simple or complex carbohydrates did not indicate significant differences in weight change. No adverse effects on blood lipids were observed. These findings underline the importance of this dietary change and its potential impact on the public health implications of obesity.