Does the timing of intake matter? Association between caffeine intake and depression: Evidence from the National Health and Nutrition Examination Survey

BACKGROUND

Recent research suggests that caffeine intake is associated with a reduced risk of depression. However, the relationship between caffeine intake during different periods of the day and depression is still unclear.

METHODS

This cross-sectional study analyzed noninstitutionalized adults from the National Health and Nutrition Examination Survey, with a weighted representation of approximately 218 million US adults. Covariate-adjusted sample-weighted regressions were used to examine associations between caffeine intake and depression in different periods.

RESULTS

Caffeine intake during non-early morning periods (outside of 5:00-8:00 AM) is associated with a high prevalence of depression (unadjusted OR: 1.08, 95%CI: 1.05-1.11; adjusted OR: 1.03, 95 % CI: 1.00-1.06). Participants who consumed caffeine in the early morning (5:00-8:00 AM) had a lower prevalence of depression compared to participants who did not consume caffeine in the early morning (unadjusted OR: 0.75, 95%CI: 0.67-0.85; adjusted OR: 0.86, 95 % CI: 0.75-0.99).

LIMITATIONS

Cross-sectional study could not determine the temporal association; patients with depression in this study were not clinically diagnosed with Major Depressive Disorder.

CONCLUSIONS

Among US adults, early morning caffeine consumers had a lower prevalence of depression than non-consumers; caffeine intake during non-early morning periods is associated with a high prevalence of depression. Our results may suggest the importance of caffeine intake time for depression.

Early morning hemodynamic changes and left ventricular hypertrophy and mortality in hemodialysis patients

INTRODUCTION

An exaggeration of the early morning increase in BP, a phenomenon accompanied by a parallel rise in heart rate (HR), is a marker of high cardiovascular risk. The early morning changes in these parameters have not been investigated in the hemodialysis population.

METHODS

In a pilot, single center study including a series of 58 patients we measured the pre-awakening BP and HR surges and the nocturnal dipping of the same parameters as well as other established indicators of autonomic function (weighted 24 h systolic BP and HR variability) and tested their relationship with the left ventricular mass index (LVMI) and with the risk of death over a median follow up of 40 months.

RESULTS

The pre-awakening HR surge (r = - 0.46, P = 0.001) but not the corresponding BP surge (r = - 0.1, P = 0.98) was associated with LVMI and the risk of death [HR (1 unit): 0.89, 95% CI 0.83-0.96, P = 0.001]. The link between the pre-awakening HR surge with these outcome measures was robust and largely independent of established risk factors in the hemodialysis population, including the nocturnal dipping of BP. Weighted 24 h systolic BP and HR variability did not correlate with LVMI (all P > 0.11) nor with the risk of death (P > 0.11) and were also independent of the nocturnal dipping of systolic BP and HR.

CONCLUSION

This pilot study suggests that the low early morning changes in HR, likely reflecting enhanced sympathetic activity, entail a high risk for left ventricular hypertrophy (LVH) and mortality in the hemodialysis population.

Impact of early-morning administration of rapid-acting insulin on the increase in blood glucose levels related to the dawn phenomenon in individuals with type 1 diabetes

Aims/Introduction

An early-morning elevation of blood glucose levels known as the dawn phenomenon and consequent postbreakfast hyperglycemia occur in some individuals with type 1 diabetes (T1D). Whereas insulin pump therapy can mitigate this phenomenon, some individuals prefer or are limited to alternative treatments. We have now assessed the effectiveness of early-morning administration of rapid-acting insulin for amelioration of the dawn phenomenon in individuals with T1D.

Materials and Methods

Thirteen individuals with T1D who experienced the dawn phenomenon as determined by continuous glucose monitoring (CGM) and who received a small dose of rapid-acting insulin on waking were included in this retrospective study. We evaluated the change in sensor glucose levels during a 2-h period from before to after breakfast consumed at 0700 h. The change in blood glucose levels during additional time intervals, average daily sensor glucose values, CGM indices, and insulin dose were also evaluated.

Results

The early-morning administration of 0.5-1 unit of rapid-acting insulin was associated with a significant reduction in 2-h glucose variability between before (0700 h) and after breakfast from a median of 90.7-51.0 mg/dL. The glucose variability from 0300 to 0700 or 0900 h was also significantly decreased, from 67.7 to 29.0 mg/dL and from 172.5 to 78.3 mg/dL, respectively. Average sensor glucose levels throughout the day were significantly reduced (from 192.7 to 156.7 mg/dL), as was the daily total insulin dose.

Conclusion

Early-morning administration of rapid-acting insulin effectively managed the dawn phenomenon and subsequent postbreakfast hyperglycemia in individuals with T1D.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13340-024-00709-6.