Jospe Michelle R, Marano Kari M, Bedoya Arianna R, Behrens Nick L, Cigan Lacey, Villegas Vanessa, Magee Michelle F, Marrero David G, Richardson Kelli M, Liao Yue, Schembre Susan M
Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, United States.
University of Arizona, Tucson, AZ, United States.
JMIR Form Res. 2023 Aug 11;7:e46034. doi: 10.2196/46034.
Glucose-guided eating (GGE) improves metabolic markers of chronic disease risk, including insulin resistance, in adults without diabetes. GGE is a timed eating paradigm that relies on experiencing feelings of hunger and having a preprandial glucose level below a personalized threshold computed from 2 consecutive morning fasting glucose levels. The dawn phenomenon (DP), which results in elevated morning preprandial glucose levels, could cause typically derived GGE thresholds to be unacceptable or ineffective among people with type 2 diabetes (T2DM).
The aim of this study is to quantify the incidence and day-to-day variability in the magnitude of DP and examine its effect on morning preprandial glucose levels as a preliminary test of the feasibility of GGE in adults with T2DM.
Study participants wore a single-blinded Dexcom G6 Pro continuous glucose monitoring (CGM) system for up to 10 days. First and last eating times and any overnight eating were reported using daily surveys over the study duration. DP was expressed as a dichotomous variable at the day level (DP day vs non-DP day) and as a continuous variable reflecting the percent of days DP was experienced on a valid day. A valid day was defined as having no reported overnight eating (between midnight and 6 AM). ∂ Glucose was computed as the difference in nocturnal glucose nadir (between midnight and 6 AM) to morning preprandial glucose levels. ∂ Glucose ≥20 mg/dL constituted a DP day. Using multilevel modeling, we examined the between- and within-person effects of DP on morning preprandial glucose and the effect of evening eating times on DP.
In total, 21 adults (59% female; 13/21, 62%) with non-insulin-treated T2DM wore a CGM for an average of 10.5 (SD 1.1) days. Twenty out of 21 participants (95%) experienced DP for at least 1 day, with an average of 51% of days (SD 27.2; range 0%-100%). The mean ∂ glucose was 23.7 (SD 13.2) mg/dL. People who experience DP more frequently had a morning preprandial glucose level that was 54.1 (95% CI 17.0-83.9; P<.001) mg/dL higher than those who experienced DP less frequently. For within-person effect, morning preprandial glucose levels were 12.1 (95% CI 6.3-17.8; P=.008) mg/dL higher on a DP day than on a non-DP day. The association between ∂ glucose and preprandial glucose levels was 0.50 (95% CI 0.37-0.60; P<.001). There was no effect of the last eating time on DP.
DP was experienced by most study participants regardless of last eating times. The magnitude of the within-person effect of DP on morning preprandial glucose levels was meaningful in the context of GGE. Alternative approaches for determining acceptable and effective GGE thresholds for people with T2DM should be explored and evaluated.
血糖引导进食（GGE）可改善无糖尿病成年人慢性疾病风险的代谢指标，包括胰岛素抵抗。GGE是一种定时进食模式，它依赖于感受饥饿感且餐前血糖水平低于根据连续两个早晨空腹血糖水平计算出的个性化阈值。黎明现象（DP）会导致早晨餐前血糖水平升高，这可能使典型的GGE阈值在2型糖尿病（T2DM）患者中不可接受或无效。
本研究旨在量化DP的发生率和每日波动幅度，并检验其对早晨餐前血糖水平的影响，作为GGE在T2DM成年患者中可行性的初步测试。
研究参与者佩戴单盲德康G6 Pro连续血糖监测（CGM）系统长达10天。在研究期间，通过每日调查记录首次和末次进食时间以及任何夜间进食情况。DP在日水平上表示为二分变量（DP日与非DP日），并作为反映有效日中经历DP天数百分比的连续变量。有效日定义为无夜间进食报告（午夜至上午6点之间）。∂血糖计算为夜间血糖最低点（午夜至上午6点之间）与早晨餐前血糖水平的差值。∂血糖≥20mg/dL构成DP日。使用多水平模型，我们检验了DP对早晨餐前血糖的个体间和个体内效应以及晚餐时间对DP的影响。
共有21名未接受胰岛素治疗的T2DM成年患者（59%为女性；13/21，62%）佩戴CGM平均10.5（标准差1.1）天。21名参与者中有20名（95%）至少有1天经历了DP，平均天数为51%（标准差27.2；范围0%-100%）。平均∂血糖为23.7（标准差13.2）mg/dL。DP发生频率较高的人的早晨餐前血糖水平比DP发生频率较低的人高54.1（95%置信区间17.0-83.9；P<0.001）mg/dL。对于个体内效应，DP日的早晨餐前血糖水平比非DP日高12.1（95%置信区间6.3-17.8；P=0.008）mg/dL。∂血糖与餐前血糖水平的关联为0.50（95%置信区间0.37-0.60；P<0.001）。末次进食时间对DP无影响。
大多数研究参与者无论末次进食时间如何都会经历DP。在GGE背景下，DP对早晨餐前血糖水平的个体内效应幅度是有意义的。应探索和评估为T2DM患者确定可接受和有效GGE阈值的替代方法。
