Seasonal Changes in Haemostatic Factors in Young and Elderly Subjects

Abstract

Morbidity and mortality from cardiovascular disease are more common in colder seasons, especially in elderly people. Previous studies have shown higher fibrinogen levels in old people in the winter months. The present studies of haemostatic factors in relation to age and season have shown that fibrinogen, tissue plasminogen activator (tPA), protein S and protein C levels are higher in old (aged 75 years and over) than young (aged 25-30 years) subjects while antiplasmin levels are lower in old people. Antiplasmin and protein C levels are lower in winter in both young and old while plasminogen activator inhibitor (PAI) is higher, and tPA higher in old people only. This study illustrates the complex interrelationships of the haemostatic system and may suggest that in 'successful' elderly people the fibrinolytic system may alter to maintain the delicate balance between thrombogenic and fibrinolytic activity. Nevertheless, the results presented here suggest that both old age and cold weather may increase the risk of atherothrombotic disease.

Diurnal, Seasonal, and Blood-Processing Patterns in Levels of Circulating Fibrinogen, Fibrin D-Dimer, C-Reactive Protein, Tissue Plasminogen Activator, and von Willebrand Factor in a 45-Year-Old Population

“…8 This is supported by other smaller studies. 7,16 As well as seasonal effects, variable reports exist of a diurnal pattern in fibrinogen 12,22,23 and D-dimer, 24 -26 whereas t-PA shows a morning peak with levels that tend to decline during the day; 12,24,27,28 vWF has been reported to show no diurnal variation in 1 small study. 28 Diurnal variation may be an important source of heterogeneity or bias, and standardization for sampling time may be important in populationbased studies, as well as in using these variables for additional coronary heart disease risk prediction in individuals.…”

“…It is possible that the seasonal pattern is a phenomenon of aging because it is not observed in young or early middle-aged healthy adults. 16,17,19 Van der Bom et al showed that the seasonal amplitude for fibrinogen was 0.29 g/L in those aged 55 to 75 years but increased to 0.43 g/L in those aged 75 years and older. 8 The seasonal heterogeneity in D-dimer (Table 1) was also small, with only 4% seasonal variation.…”

“…5 Several studies have shown seasonal variation in fibrinogen, with the highest levels in the winter months, 6 -14 although 1 study demonstrated a peak in early summer 15 and 3 studies did not find a seasonal effect for fibrinogen. 16 -18 Variable reports exist for seasonality of CRP, 6,7,11,19 while t-PA shows a winter peak 12,16 and there is no data for vWF or D-dimer. One postulated cause for these seasonal effects is an increase in respiratory infections that leads to a rise in levels of acute-phase reactant proteins such as fibrinogen and CRP 6,7 in the colder months, which produces a hypercoagulable and inflammatory state that may be partly responsible for the rise in cardiovascular morbidity and mortality in the winter months, especially in the elderly.…”

“…One postulated cause for these seasonal effects is an increase in respiratory infections that leads to a rise in levels of acute-phase reactant proteins such as fibrinogen and CRP 6,7 in the colder months, which produces a hypercoagulable and inflammatory state that may be partly responsible for the rise in cardiovascular morbidity and mortality in the winter months, especially in the elderly. 6,16 …”

Seasonal variation of C-reactive protein and atherosclerotic cardiovascular events in hemodialysis patients

“…[10][11][12][13][14] However, some other studies did not confirm these findings. [15][16][17] The variation in inflammatory response is even greater in patients with established ACVD confirming the dynamic inflammatory status in these patients. 18 Seasonal variations in the incidence of cardiovascular events have also been reported by several investigators with a peak in winter months.…”