Race- and sex-specific associations of obesity measures with ischemic stroke incidence in the Atherosclerosis Risk in Communities (ARIC) study

Measures of adiposity and risk of stroke in China: a result from the Kailuan study

Objective

The objective of this study was to explore the association between adiposity and risk of incident stroke among men and women.

Methods

We studied the relationship between adiposity and stroke among 94,744 participants (18–98 years old) in the Kailuan study. During a follow-up of 4 years, 1,547 ischemic or hemorrhagic strokes were recorded. Measurements of adiposity included body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHpR), and waist-to-height ratio (WHtR). Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated from Cox regression models and each model fit was assessed using −2log-likelihood.

Results

Every measurement of adiposity was associated with the risk for total stroke and ischemic stroke, but not for hemorrhagic stroke. After adjusting for confounders and intermediates, the HR (comparing the mean of the highest quintile with that of the lowest quintile) for total stroke was 1.34(1.13–1.60) for BMI, 1.26(1.06–1.52) for WC, 1.29(1.08–1.56) for WHpR, and 1.38(1.15–1.66) for WHtR. The HR for ischemic stroke was 1.52(1.24–1.88) for BMI, 1.46(1.17–1.81) for WC, 1.40(1.12–1.74) for WHpR, and 1.62(1.29–2.04) for WHtR. The model fit for each of the indices was similar.

Conclusions

Adiposity increases the total risk of stroke and ischemic stroke, but not of hemorrhagic stroke. No clinically meaningful differences among the associations between BMI, WC, WHpR, and WHtR and stroke incidence were identified in this study.

Time-dependent impact of diabetes on mortality in patients with stroke: survival up to 5 years in a health insurance population cohort in Germany

OBJECTIVE

To estimate the impact of diabetes on mortality in patients after first stroke event.

RESEARCH DESIGN AND METHODS

Using claims data from a nationwide statutory health insurance fund (Gmünder ErsatzKasse), we assessed all deaths in a cohort of 5,757 patients with a first stroke between 2005 and 2007 (69.3% male, mean age 68.1 years, 32.2% with diabetes) up to 2009. By use of Cox regression, we estimated time-dependent hazard ratios (HRs) to compare patients with and without diabetes stratified by sex.

RESULTS

The cumulative 5-year mortality was 40.0 and 54.2% in diabetic men and women, and 32.3 and 38.1% in their nondiabetic counterparts, respectively. In males, mortality was significantly lower in diabetic compared with nondiabetic patients in the first 30 days (multiple-adjusted HR 0.67 [95% CI 0.53-0.84]). After approximately a quarter of a year, the diabetes risk increased, yielding crossed survival curves. Later on, mortality risk tended to be similar in diabetic and nondiabetic men (1-2 years: 1.42 [1.09-1.85]; 3-5 years: 1.00 [0.67-1.41]; time dependency of diabetes, P = 0.008). In women, the pattern was similar; however, time dependency was not statistically significant (P = 0.89). Increasing age, hemorrhagic stroke, renal failure (only in men), levels of care dependency, and number of prescribed medications were significantly associated with mortality.

CONCLUSIONS

We found a time-dependent mortality risk of diabetes after first stroke in men. Possible explanations may be type of stroke or earlier and more intensive treatment of risk factors in diabetic patients.

Epidemiology and prevention of stroke: a worldwide perspective

This paper reviews how epidemiological studies during the last 5 years have advanced our knowledge in addressing the global stroke epidemic. The specific objectives were to review the current evidence supporting management of ten major modifiable risk factors for prevention of stroke: hypertension, current smoking, diabetes, obesity, poor diet, physical inactivity, atrial fibrillation, excessive alcohol consumption, abnormal lipid profile and psychosocial stress/depression.

Measures of Abdominal Adiposity and the Risk of Stroke

Background and Purpose—

Excess fat accumulates in the subcutaneous and visceral adipose tissue compartments. We tested the hypothesis that indicators of visceral adiposity, namely, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), are better predictors of stroke risk than body mass index (BMI).

Methods–

The association of BMI, WC, WHR, and WHtR with stroke was assessed in 31 201 men and 23 516 women, free of vascular disease at baseline, from the MOnica Risk, Genetics, Archiving and Monograph (MORGAM) study. During a mean follow-up of 11 years, 1130 strokes were recorded. Relative risks (95% CI) were calculated by Cox regression after stratification for center and adjustment for age, smoking, educational level, alcohol consumption, hypertension, diabetes, total cholesterol, high-density lipoprotein cholesterol, and BMI and model fit was assessed using log-likelihoods.

Results—

BMI, WC, WHR, and WHtR were associated with the risk of stroke in men. After full adjustment including BMI, the relative risks for stroke remained significant for WC (1.19 [1.02 to 1.34] per 1 SD increase in WC), WHR (1.14 [1.03 to 1.26]), and WHtR (1.50 [1.28 to 1.77]). Among women, the extent of the associations with stroke risk was similar for WHtR (1.31 [1.04 to 1.65]), WC (1.19 [0.96 to 1.47]), and WHR (1.08 [0.97 to 1.22]). Further analyses by World Health Organization obesity categories showed that WC, WHR, and WHtR were associated with the risk of stroke also in lean men and women (BMI <25 kg/m 2 ), independently of confounders, cardiovascular risk factors, and BMI.

Conclusions—

Indicators of abdominal adiposity, especially WHtR, are more strongly associated with stroke risk than BMI. These results emphasize the importance of measuring abdominal adiposity, especially in lean subjects.

No Time to ‘Weight’: The Link between Obesity and Stroke in Women

The obesity epidemic in the USA threatens the gains that have been made in the prevention and treatment of stroke. Both obesity and stroke disproportionately affect women more than men. Understanding the effect of obesity on stroke risk in women may be a useful stepping stone to reducing the burden of stroke in this vulnerable population. This article reviews the association between stroke and general obesity, abdominal obesity and metabolic syndrome in women. All three factors have been shown to independently increase stroke risk in women.

Estrogen receptor alpha and beta are both involved in the cerebral VEGF/Akt/NO pathway and cerebral angiogenesis in female mice

We have previously demonstrated that vascular endothelial growth factor (VEGF) is critical for cerebral angiogenesis in middle-aged female rats and may play a role in the flow-preserving neuroprotective actions of estrogen through its angiogenic and antiapoptotic properties. Here, we attempt to elucidate the effects of estrogen and the specific estrogen receptor (ER) subtype in cerebral VEGF/Akt/NO pathways and cerebral angiogenesis using 15-week old female mice that are either wild-type (WT), lack estrogen receptor α (ERαKO) or β (ERβKO). Protein levels of VEGF and basic signaling molecules of VEGF angiogenic pathway in the frontal cortex were expressed as follows, as revealed by ELISA and immunoblotting : a) VEGF; WT: ERαKO: ERβKO, 47 ± 15: 27 ± 5: 28 ± 5 pg/mg, respectively (P < 0.01); b) KDR decreased about 40% in both ERαKO and ERβKO compared to WT; c) Akt was significantly down-regulated in both ERαKO and ERβKO compared to WT; d) phosphorylated Akt (pAkt); WT: ERαKO: ERβKO, 0.6 ± 0.2: 0.3 ± 0.01: 0.3 ± 0.1 units/mg, respectively; e) phosphorylated eNOS significantly decreased about 45% in both ERαKO and ERβKO compared to WT. Cerebral capillary density decreased in both ERαKO and ERβKO compared to WT. Thus, it can be concluded that in female mice, VEGF/Akt/eNOS pathway plays an important role in cerebral angiogenesis and that both ER subtypes are involved in the regulation of VEGF and its signaling molecule expression in the frontal cortex.

A clinical follow-up study on the risk of cerebral infarction in Chinese aging overweight and obese population

SUMMARY

The current studies have shown that overweight and obesity are possible risk factors for cerebral infarction, but variety of weight status in the role of the mechanism of cerebral infarction is not yet fully understood. In our research, a prospective cohort follow-up study of 8 years (2002-2009) was used to analyze the correlation of weight, cerebral infarction and other factors in 1170 Han retired employees from KaiLuan Group. The study included enrolling with questionnaire survey, medical examination, brain CT scan and so on, based on the changes in body mass index from the beginning to the end of the follow-up study, the subjects were divided into eight groups: stay normal weight group (n = 364), stay overweight group (n = 171), development from overweight into obesity group (n = 95), stay obesity group (n = 37), development from normal weight into overweight group (n = 365), development from normal weight into obesity group (n = 63), overweight improved group (n = 55) and obesity improved group (n = 20). We found that the incidence of cerebral infarction in the stay overweight group was higher than in the stay obese and stay normal weight groups (25.15%, 18.92%, 19.23%, P < 0.05) during the last medical examination in the end of follow-up study, and relative risk was 1.31, 0.98, 1, and population attributable risk was 0.10, -0.002, 0, respectively. But there was no difference of the incidence of cerebral infarction between stay obesity group and stay normal weight group (P > 0.05). The incidence of hypertension in the development of normal weight into obesity group and stay obesity group was higher than stay overweight group and stay normal weight group (63.49%, 56.76%, 48.54%, 36.54%, P < 0.05), while the aggregated incidence of risk factors in above mentioned four groups was 75%, 64%, 63%, 55% (P < 0.05), respectively. In logistic regression analysis of correlative factors to cerebral infarction, waist circumference in the last checkup, diabetes, development from normal weight to overweight status, etc were selected (P < 0.01), and odds ratio (OR) values were 0.98, 6.51, 4.13 (P < 0.05), respectively. The incidence of cerebral infarction in overweight improved and obesity improved groups were 29.09%, 45.00%, relative risk values were 1.51, 2.34, the aggregated incidence of risk factors were 48%, 65%. This study showed that Chinese aging population who has overweight with a significant overweight stable phase and with no overweight stable phase but progressing to obesity had different risks of diseases. The former was at high risk of cerebral infarction, the latter was susceptible to hypertension. In the aging population of overweight and obesity, the aggregated incidence of cerebral infarction related risk factors were significantly increased, and weight-loss treatment did not reduce the incidence of cerebral infarction. Thus, the aging patients with obesity should be actively treated to eliminate hypertension and other risk factors, rather than an appetite for weight-loss treatment.:

Emerging risk factors in women

Stroke is a major cause of long-term disability and death for women in the United States, with recent evidence suggesting a higher rate of stroke in midlife women than men, as well as higher lifetime risk of stroke for older women. Several recent studies highlight emerging areas of interest for research on risk factors for stroke in women. This article reviews data published in the last year, focusing on 3 potential risk factors that may partially explain these differences between men and women: central adiposity and related adipocytokines, endogenous sex hormones, and depression.

Body mass index, weight change and risk of stroke and stroke subtypes: the Japan Public Health Center-based prospective (JPHC) study

OBJECTIVE

The Japan Public Health Center-based prospective Study examined the association of body mass index (BMI) and weight change with incident stroke in Japanese individuals, for whom BMI levels are generally low.

METHODS

We used initial data from 1990 to 1994 and 5-year follow-up surveys from 1995 to 1999. We calculated weight change over a 5-year period for 32,847 men and 38,875 women, aged 45-74 years, with no history of cardiovascular disease or cancer. Subjects were followed from the 1995-1999 survey to the end of 2005, and hazard ratios of self-reported BMI levels and weight change for incident stroke were estimated using Cox's proportional hazard models adjusted for potential confounders.

RESULTS

During the follow-up period (median 7.9 years) there were 2019 incident strokes, including subtypes. Multivariable-adjusted hazard ratios for all stroke events by BMI levels of 27.0-29.9 and ≥ 30 kg m(-2) versus 23.0-24.9 kg m(-2) were 1.09 (95% confidence interval 0.88, 1.36) and 1.25 (0.86, 1.84) in men (P for trend=0.22), and 1.29 (1.01, 1.65) and 2.16 (1.60, 2.93) in women (P for trend <0.001), respectively. A weight change of ≥ 10% in the previous 5 years was associated with total strokes and ischemic strokes in women.

CONCLUSION

Higher BMI levels and a weight gain of ≥ 10% over 5 years were associated with an increased risk of stroke in women, whereas this association was weak in men.