Link Between Poor Sleep and Low Grade Inflammation Discovered

Persons sleeping less than 6 hours or more than 10 hours suffer from low-grade inflammation more often than persons sleeping 7-8 hours per night. This was observed in a University of Eastern Finland study focusing on the health and lifestyle habits among middle-aged men.

“Earlier studies have found a relation between reduced sleep and low-grade inflammation,” says Maria Luojus, MHSc, one of the study researchers.

Furthermore, low-grade inflammation occurs in overweight, depression and diabetes.

The study is the first to analyse the association between sleep duration and serum micronutrient concentrations in a large sample, and it found a link between high serum copper concentration and long sleep duration. Serum micronutrient concentrations are affected by many factors, including an individual’s general health and diet.

“Based on this study, however, it is impossible to say whether sleeping long results in high serum copper concentrations or vice versa,” Luojus says.

It has been suggested that high serum copper concentration associates with pro-oxidative stress.

Image shows a sleeping man.
The study is the first to analyse the association between sleep duration and serum micronutrient concentrations in a large sample, and it found a link between high serum copper concentration and long sleep duration. Image is for illustrative purposes only.

“Pro-oxidative stress is found in many chronic diseases, such as coronary artery disease. Nevertheless, when the study participants’ cardiovascular diseases were taken account for, our results remained unchanged. The association between serum copper concentration and sleep duration persisted independently of cardiovascular diseases,” Luojus says.

In addition to, the study participants’ age, cumulative smoking history, alcohol consumption, depressive symptoms, physical activity and metabolic syndrome were taken into account in the data analysis.

About this sleep research

The study involved 2,682 men living in Eastern Finland, participating the Kuopio Ischemic Heart Disease Risk Factor (KIHD) study. The KIHD study has been ongoing at the University of Eastern Finland in the Institute of Public Health and Clinical Nutrition since 1984.

Source: Maria Luojus – University of Eastern Finland
Image Source: The image is in the public domain
Original Research: Abstract for “Serum copper, zinc and high-sensitivity C-reactive protein in short and long sleep duration in ageing men” by Maria K. Luojus, Soili M. Lehto, Tommi Tolmunen, Antti-Pekka Elomaa, and Jussi Kauhanen in Journal of Trace Elements in Medicine and Biology. Published online July 22 2015 doi:10.1016/j.jtemb.2015.07.008


Abstract

Serum copper, zinc and high-sensitivity C-reactive protein in short and long sleep duration in ageing men

Background

Serum levels of zinc and copper have been proposed to associate with sleep duration. Mechanisms, such as inflammatory processes, have been suggested to relate this association. However, earlier studies have been conducted in small sample sizes. Human studies investigating the suggested associations while controlling for potential confounding factors are lacking.

Methods

Population-based data consisted of 2570 men (aged 42–60 years) from Eastern Finland. The participants reported an estimate of their sleep duration. The serum levels of zinc (S–Zn), copper (S–Cu) and high-sensitivity C-reactive protein (hs-CRP) were measured. Analysis of covariance was used for multivariate analyses.

Results

S–Zn levels and Zn/Cu ratio were lowest in ≤6 h sleep. S–Cu levels were highest in ≥10 h sleep. Elevated levels (>3.0 mmol/l) of hs-CRP were observed in ≤6 h and ≥10 h sleep. After adjustments for age, cumulative smoking history (pack-years), alcohol consumption (g/week), Human Population Laboratory depression scale scores, physical activity (kcal/day), cardiometabolic syndrome, and cardiovascular disease history, sleep duration was significantly associated with levels of both S–Cu and hs-CRP. The association with S–Cu remained statistically significant following further adjustment for hs-CRP in the same model.

Conclusions

Our data suggests an association between S–Cu and sleep duration in ageing men. Elevated inflammation (measured as serum hs-CRP) does not explain this relationship. Mechanisms underlying the relationship require further investigation, as S–Cu may contribute to sleep regulation through pro-oxidative processes and copper-dependent N-methyl-d-aspartate receptor activity.

“Serum copper, zinc and high-sensitivity C-reactive protein in short and long sleep duration in ageing men” by Maria K. Luojus, Soili M. Lehto, Tommi Tolmunen, Antti-Pekka Elomaa, and Jussi Kauhanen in Journal of Trace Elements in Medicine and Biology. Published online July 22 2015 doi:10.1016/j.jtemb.2015.07.008

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