BACKGROUND: Overweight and obesity increase the risk of elevated blood pressure, but the knowledge of the effect of weight change on blood pressure is sparse. OBJECTIVE: To investigate the association between change in body mass index (BMI) and change in diastolic blood pressure (DBP), systolic blood pressure (SBP), and hypertension status. DESIGN: Two population-based cross-sectional studies, one in 1984-86 and the other in 1995-97. SETTING: The Nord-Trøndelag Health Study (HUNT). PARTICIPANTS: We included 15 971 women and 13 846 men who were 20 y or older at the first survey, without blood pressure medication at both surveys and without diabetes, cardiovascular disease or dysfunction in daily life at baseline. MEASUREMENTS: Weight, height and blood pressure were measured standardised. Change in BMI was categorised as stable (initial BMI70.1 kg/m 2 each follow-up year), increased or decreased, and BMI was categorised by using World Health Organisation's categorisation (underweight BMI: o18.5 kg/m 2 , normal weight BMI: 18.5-24.9 kg/m 2 , overweight BMI: 25.0-29.9 kg/m 2 , obesity BMIZ30 kg/m 2 ). RESULTS: An increase in BMI and a decrease in BMI were significantly associated with increased and decreased SBP and DBP, respectively, compared to a stable BMI in both genders and all age groups, although the strongest effect was found among those who were 50 y and older. The adjusted odds ratio for having hypertension at HUNT 2 was 1.8 (95% confidence interval (CI): 1.5, 2.2) among women and 1.6 (95% CI: 1.4,1.8) among men aged 20-49 y who increased their BMI compared to those who had stable BMI. A similar, but weaker association was found among women and men aged 50 y or more. The mean change in both SBP and DBP was higher for those who changed BMI category from first to the second survey than for those who were in the same BMI class at both surveys. CONCLUSIONS: Our result supports an independent effect of change in BMI on change in SBP and DBP in both women and men, and that people who increase their BMI are at increased risk for hypertension. The exact mechanism whereby change in body weight causes elevated blood pressure is still unknown. Hypertension and the risk of having cardiovascular disease are strongly linked 5,6 and to investigate the effect on blood pressure when the body weight changes is important in a public health perspective. In Nord-Trøndelag County, Norway, two large health surveys were conducted in 1984-86 (HUNT 1) and 1995-97 (HUNT 2), respectively, with information on weight, height and blood pressure. This gave us the opportunity to prospectively examine the association between change in body mass index (BMI) and its impact on blood pressure during a 11-y follow-up in a large population of both men and women aged 20 y or more. Methods Study populationIn the first health survey (HUNT 1, 1984-86), all citizens residing in the county aged 20 y and older (n ¼ 85 100) were ). Change in BMI between the surveys was categorised into stable, increased and decreased with stable defined as BMI at first ...

Objective: The aim of this study was to analyse changes in body weight and height, and the changes in the prevalence of overweight and obesity. Design: Prospective population based study with 11-year follow-up. Subjects: Norwegian men (n ¼ 21565) and women (n ¼ 24337) aged 20 years or more who participated in two health surveys, the first in 1984-1986 and the other in 1995-1997. Measurements: Height and weight were measured by using standardised procedures at both surveys, and we computed body mass index (BMI) as weight in kilo divided by the squared value of height in meters. Results: Participants who were younger than 50 years at the first survey showed a large increase in body weight, and men and women aged 20-29 years increased their weight with an average of 7.9 kg and 7.3 kg, respectively. Contradictory, participants who were 70 years or older had on average a weight loss. The prevalence of overweight (BMI ¼ 25.0-29.9 kg/m 2 ) and obesity (BMIX30 kg/m 2 ) increased between the surveys, especially in the youngest age groups. Overall, the proportion classified as obese increased from 6.7 to 15.5% among men and from 11.0 to 21.0% among women. Some of this increase was due to a reduction in height, which was most pronounced in the oldest age groups. Conclusion: During approximately 10 years, body weight increased in all age groups below 70 years, and the prevalence of overweight and obese persons was approximately 20% higher at the second survey compared with the first survey.

The authors investigated the shape, sex- and age-dependency, and possible confounding of the association between birth weight and systolic blood pressure (SBP) in 197,954 adults from 20 Nordic cohorts (birth years 1910-1987), one of which included 166,249 Swedish male conscripts. Random-effects meta-regression analyses were performed on estimates obtained from age- and sex-stratified analyses within each of the cohorts. There was an inverse association between birth weight and SBP, irrespective of adjustment for concurrent body mass index. The association was linear for males, but for females with a birth weight greater than 4 kg, SBP increased with birth weight (p < 0.01). The association was stronger in the older age groups (p < 0.05), although this could have been a birth cohort effect. The association was stronger among females than among males (p = 0.005) when birth weight was less than or equal to 4 kg. The estimated effect of birth weight on SBP at age 50 years was -1.52 mmHg/kg (95% confidence interval: -2.27, -0.77) in men and -2.80 mmHg/kg (95% confidence interval: -3.85, -1.76) in women. Exclusion of the Swedish conscripts produced nearly identical results. This meta-analysis supports the evidence of an inverse birth weight-SBP association, regardless of adjustment for concurrent body size. It also reveals important heterogeneity in the shape and strength of the association by sex and age.