Gut microbiota have also been linked to hypertension, especially in experimental Some of the best-proven environmental rela- tionships with high BP are briefly reviewed below, and non- pharmacological interventions to lower BP are discussed in Section 6.2. 5.2.1. Overweight and Obesity Insurance industry actuarial reports have identified a strik- ing relationship between body weight and high BPS5.2.1-1 and a direct relationship between overweight/obesity and Epidemiological studies, including the Framingham Heart StudyS5.2.1-3 and the Nurses Health have consistently identified a direct relation- ship between body mass index and BP that is continuous and almost linear, with no evidence of a threshold.S5.2.1-5,S5.2.1-6 The relationship with BP is even stronger for waist-to- hip ratio and computed tomographic measures of central Attributable risk estimates from the Nurses Health Study suggest that obesity may be respon- sible for about 40% of hypertension, and in the Framingham Offspring Study, the corresponding estimates were even Figure 2. Detection of white coat effect or masked uncontrolled hypertension in patients on drug therapy. Colors correspond to Class of Recommendation in Table 1. See Section 8 for treatment options. ABPM indicates ambulatory blood pressure monitoring; BP, blood pressure; CVD, cardiovascular disease; and HBPM, home blood pressure monitoring. Whelton et al 2017 High Blood Pressure Clinical Practice Guideline e29 higher (78% in men and 65% in women).S5.2.1-8,S5.2.1-9 The relationship between obesity at a young age and change in obesity status over time is strongly related to future risk of hypertension. In combined data from 4 longitudinal stud- ies begun in adolescence with repeat examination in young adulthood to early middle age, being obese continuously or acquiring obesity was associated with a relative risk of 2.7 for developing hypertension. Becoming normal weight reduced the risk of developing hypertension to a level similar to those who had never been obese.S5.2.1-10 5.2.2. 